Subjects -> MATHEMATICS (Total: 1013 journals)
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    - MATHEMATICS (714 journals)
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MATHEMATICS (714 journals)                  1 2 3 4 | Last

Showing 1 - 200 of 538 Journals sorted alphabetically
Abakós     Open Access   (Followers: 3)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 2)
Accounting Perspectives     Full-text available via subscription   (Followers: 4)
ACM Transactions on Algorithms (TALG)     Hybrid Journal   (Followers: 13)
ACM Transactions on Computational Logic (TOCL)     Hybrid Journal   (Followers: 5)
ACM Transactions on Mathematical Software (TOMS)     Hybrid Journal   (Followers: 6)
ACS Applied Materials & Interfaces     Hybrid Journal   (Followers: 39)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 2)
Acta Mathematica Hungarica     Hybrid Journal   (Followers: 3)
Acta Mathematica Sinica, English Series     Hybrid Journal   (Followers: 5)
Acta Mathematica Vietnamica     Hybrid Journal  
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal  
Advanced Science Letters     Full-text available via subscription   (Followers: 9)
Advances in Applied Clifford Algebras     Hybrid Journal   (Followers: 5)
Advances in Catalysis     Full-text available via subscription   (Followers: 7)
Advances in Complex Systems     Hybrid Journal   (Followers: 10)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 20)
Advances in Decision Sciences     Open Access   (Followers: 4)
Advances in Difference Equations     Open Access   (Followers: 2)
Advances in Fixed Point Theory     Open Access  
Advances in Geosciences (ADGEO)     Open Access   (Followers: 19)
Advances in Linear Algebra & Matrix Theory     Open Access   (Followers: 9)
Advances in Materials Science     Open Access   (Followers: 19)
Advances in Mathematical Physics     Open Access   (Followers: 5)
Advances in Mathematics     Full-text available via subscription   (Followers: 19)
Advances in Numerical Analysis     Open Access   (Followers: 4)
Advances in Operations Research     Open Access   (Followers: 13)
Advances in Operator Theory     Hybrid Journal  
Advances in Pure Mathematics     Open Access   (Followers: 8)
Advances in Science and Research (ASR)     Open Access   (Followers: 8)
Aequationes Mathematicae     Hybrid Journal   (Followers: 2)
African Journal of Educational Studies in Mathematics and Sciences     Full-text available via subscription   (Followers: 7)
African Journal of Mathematics and Computer Science Research     Open Access   (Followers: 5)
Afrika Matematika     Hybrid Journal   (Followers: 2)
Air, Soil & Water Research     Open Access   (Followers: 6)
AKSIOMATIK : Jurnal Penelitian Pendidikan dan Pembelajaran Matematika     Open Access  
Al-Jabar : Jurnal Pendidikan Matematika     Open Access  
Al-Qadisiyah Journal for Computer Science and Mathematics     Open Access   (Followers: 2)
AL-Rafidain Journal of Computer Sciences and Mathematics     Open Access   (Followers: 3)
Algebra and Logic     Hybrid Journal   (Followers: 7)
Algebra Colloquium     Hybrid Journal   (Followers: 1)
Algebra Universalis     Hybrid Journal   (Followers: 2)
Algorithmic Operations Research     Open Access   (Followers: 5)
Algorithms     Open Access   (Followers: 13)
Algorithms Research     Open Access   (Followers: 1)
American Journal of Computational and Applied Mathematics     Open Access   (Followers: 8)
American Journal of Mathematical Analysis     Open Access   (Followers: 1)
American Journal of Mathematical and Management Sciences     Hybrid Journal  
American Journal of Mathematics     Full-text available via subscription   (Followers: 8)
American Journal of Operations Research     Open Access   (Followers: 6)
American Mathematical Monthly     Full-text available via subscription   (Followers: 3)
An International Journal of Optimization and Control: Theories & Applications     Open Access   (Followers: 12)
Analele Universitatii Ovidius Constanta - Seria Matematica     Open Access  
Analysis and Applications     Hybrid Journal   (Followers: 2)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 9)
Anargya : Jurnal Ilmiah Pendidikan Matematika     Open Access  
Annales Mathematicae Silesianae     Open Access  
Annales mathématiques du Québec     Hybrid Journal   (Followers: 3)
Annales Universitatis Mariae Curie-Sklodowska, sectio A – Mathematica     Open Access   (Followers: 1)
Annales Universitatis Paedagogicae Cracoviensis. Studia Mathematica     Open Access  
Annali di Matematica Pura ed Applicata     Hybrid Journal   (Followers: 1)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Data Science     Hybrid Journal   (Followers: 14)
Annals of Functional Analysis     Hybrid Journal   (Followers: 2)
Annals of Mathematics     Full-text available via subscription   (Followers: 4)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 16)
Annals of PDE     Hybrid Journal  
Annals of Pure and Applied Logic     Open Access   (Followers: 4)
Annals of the Alexandru Ioan Cuza University - Mathematics     Open Access   (Followers: 1)
Annals of the Institute of Statistical Mathematics     Hybrid Journal   (Followers: 1)
Annals of West University of Timisoara - Mathematics     Open Access   (Followers: 1)
Annuaire du Collège de France     Open Access   (Followers: 6)
ANZIAM Journal     Open Access   (Followers: 1)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 3)
Applications of Mathematics     Hybrid Journal   (Followers: 2)
Applied Categorical Structures     Hybrid Journal   (Followers: 4)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 16)
Applied Mathematics     Open Access   (Followers: 7)
Applied Mathematics     Open Access   (Followers: 6)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 11)
Applied Mathematics - A Journal of Chinese Universities     Hybrid Journal   (Followers: 1)
Applied Mathematics and Nonlinear Sciences     Open Access  
Applied Mathematics Letters     Full-text available via subscription   (Followers: 1)
Applied Mathematics Research eXpress     Hybrid Journal   (Followers: 1)
Applied Network Science     Open Access   (Followers: 2)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 4)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5)
Arab Journal of Mathematical Sciences     Open Access   (Followers: 3)
Arabian Journal of Mathematics     Open Access   (Followers: 1)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 3)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 4)
Archive of Numerical Software     Open Access  
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
Armenian Journal of Mathematics     Open Access  
Arnold Mathematical Journal     Hybrid Journal   (Followers: 1)
Artificial Satellites     Open Access   (Followers: 21)
Asia-Pacific Journal of Operational Research     Hybrid Journal   (Followers: 3)
Asian Journal of Algebra     Open Access   (Followers: 1)
Asian Research Journal of Mathematics     Open Access  
Asian-European Journal of Mathematics     Hybrid Journal   (Followers: 2)
Australian Mathematics Teacher, The     Full-text available via subscription   (Followers: 7)
Australian Primary Mathematics Classroom     Full-text available via subscription   (Followers: 4)
Australian Senior Mathematics Journal     Full-text available via subscription   (Followers: 1)
Automatic Documentation and Mathematical Linguistics     Hybrid Journal   (Followers: 5)
Axioms     Open Access   (Followers: 1)
Baltic International Yearbook of Cognition, Logic and Communication     Open Access   (Followers: 2)
Banach Journal of Mathematical Analysis     Hybrid Journal  
Basin Research     Hybrid Journal   (Followers: 7)
BIBECHANA     Open Access  
Biomath     Open Access  
BIT Numerical Mathematics     Hybrid Journal  
Boletim Cearense de Educação e História da Matemática     Open Access  
Boletín de la Sociedad Matemática Mexicana     Hybrid Journal  
Bollettino dell'Unione Matematica Italiana     Full-text available via subscription  
British Journal for the History of Mathematics     Hybrid Journal   (Followers: 1)
British Journal of Mathematical and Statistical Psychology     Full-text available via subscription   (Followers: 17)
Buletinul Academiei de Stiinte a Republicii Moldova. Matematica     Open Access   (Followers: 1)
Bulletin des Sciences Mathamatiques     Full-text available via subscription   (Followers: 3)
Bulletin of Dnipropetrovsk University. Series : Communications in Mathematical Modeling and Differential Equations Theory     Open Access   (Followers: 2)
Bulletin of Mathematical Sciences     Open Access   (Followers: 1)
Bulletin of Symbolic Logic     Full-text available via subscription   (Followers: 4)
Bulletin of Taras Shevchenko National University of Kyiv. Series: Physics and Mathematics     Open Access  
Bulletin of the Australian Mathematical Society     Full-text available via subscription   (Followers: 2)
Bulletin of the Brazilian Mathematical Society, New Series     Hybrid Journal  
Bulletin of the Iranian Mathematical Society     Hybrid Journal  
Bulletin of the London Mathematical Society     Hybrid Journal   (Followers: 3)
Bulletin of the Malaysian Mathematical Sciences Society     Hybrid Journal  
Cadernos do IME : Série Matemática     Open Access  
Calculus of Variations and Partial Differential Equations     Hybrid Journal  
Canadian Journal of Mathematics / Journal canadien de mathématiques     Hybrid Journal  
Canadian Journal of Science, Mathematics and Technology Education     Hybrid Journal   (Followers: 20)
Canadian Mathematical Bulletin     Hybrid Journal  
Carpathian Mathematical Publications     Open Access  
Catalysis in Industry     Hybrid Journal  
CAUCHY     Open Access   (Followers: 1)
CEAS Space Journal     Hybrid Journal   (Followers: 6)
CHANCE     Hybrid Journal   (Followers: 5)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 1)
Chaos, Solitons & Fractals : X     Open Access   (Followers: 1)
ChemSusChem     Hybrid Journal   (Followers: 7)
Chinese Annals of Mathematics, Series B     Hybrid Journal  
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Mathematics     Open Access  
Ciencia     Open Access  
CODEE Journal     Open Access  
Cogent Mathematics     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 2)
Collectanea Mathematica     Hybrid Journal  
College Mathematics Journal     Hybrid Journal   (Followers: 3)
COMBINATORICA     Hybrid Journal  
Combinatorics, Probability and Computing     Hybrid Journal   (Followers: 4)
Combustion Theory and Modelling     Hybrid Journal   (Followers: 18)
Commentarii Mathematici Helvetici     Hybrid Journal   (Followers: 1)
Communications in Combinatorics and Optimization     Open Access  
Communications in Contemporary Mathematics     Hybrid Journal  
Communications in Mathematical Physics     Hybrid Journal   (Followers: 2)
Communications On Pure & Applied Mathematics     Hybrid Journal   (Followers: 6)
Complex Analysis and its Synergies     Open Access   (Followers: 2)
Complex Variables and Elliptic Equations: An International Journal     Hybrid Journal  
Compositio Mathematica     Full-text available via subscription   (Followers: 1)
Comptes Rendus : Mathematique     Open Access  
Computational and Applied Mathematics     Hybrid Journal   (Followers: 3)
Computational and Mathematical Methods     Hybrid Journal  
Computational and Mathematical Methods in Medicine     Open Access   (Followers: 2)
Computational and Mathematical Organization Theory     Hybrid Journal   (Followers: 1)
Computational Complexity     Hybrid Journal   (Followers: 5)
Computational Mathematics and Modeling     Hybrid Journal   (Followers: 8)
Computational Mechanics     Hybrid Journal   (Followers: 11)
Computational Methods and Function Theory     Hybrid Journal  
Computational Optimization and Applications     Hybrid Journal   (Followers: 9)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 9)
Confluentes Mathematici     Hybrid Journal  
Constructive Mathematical Analysis     Open Access  
Contributions to Discrete Mathematics     Open Access  
Contributions to Game Theory and Management     Open Access  
COSMOS     Hybrid Journal   (Followers: 1)
Cross Section     Full-text available via subscription   (Followers: 1)
Cryptography and Communications     Hybrid Journal   (Followers: 11)
Cuadernos de Investigación y Formación en Educación Matemática     Open Access  
Cubo. A Mathematical Journal     Open Access  
Current Research in Biostatistics     Open Access   (Followers: 8)
Czechoslovak Mathematical Journal     Hybrid Journal  
Daya Matematis : Jurnal Inovasi Pendidikan Matematika     Open Access  
Demographic Research     Open Access   (Followers: 14)
Design Journal : An International Journal for All Aspects of Design     Hybrid Journal   (Followers: 33)
Desimal : Jurnal Matematika     Open Access  
Dhaka University Journal of Science     Open Access  
Differential Equations and Dynamical Systems     Hybrid Journal   (Followers: 2)
Differentsial'nye Uravneniya     Open Access  
Digital Experiences in Mathematics Education     Hybrid Journal   (Followers: 2)
Discrete Mathematics     Hybrid Journal   (Followers: 8)
Discrete Mathematics & Theoretical Computer Science     Open Access   (Followers: 1)
Discrete Mathematics, Algorithms and Applications     Hybrid Journal   (Followers: 2)
Discussiones Mathematicae - General Algebra and Applications     Open Access  
Discussiones Mathematicae Graph Theory     Open Access   (Followers: 1)
Diskretnaya Matematika     Full-text available via subscription  
Doklady Akademii Nauk     Open Access  
Doklady Mathematics     Hybrid Journal  
Eco Matemático     Open Access  
Econometrics     Open Access   (Followers: 2)

        1 2 3 4 | Last

Similar Journals
Journal Cover
Discrete Mathematics, Algorithms and Applications
Number of Followers: 2  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1793-8309 - ISSN (Online) 1793-8317
Published by World Scientific Homepage  [120 journals]
  • Average degree matrix and average degree energy

    • Free pre-print version: Loading...

      Authors: H. S. Sujatha
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      If [math] is a simple graph on [math] vertices [math] and [math] be the degree of [math]th vertex [math] then the average degree matrix of graph [math], [math] is of order [math] whose [math]th entry is [math] if the vertices [math] and [math] are adjacent and zero otherwise. The average degree energy of [math], [math] is the sum of all absolute value of eigenvalues of average degree matrix of a graph [math]. In this paper, bounds for average degree energy [math] and the relation between average degree energy [math] and energy [math] is discussed.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-05-20T07:00:00Z
      DOI: 10.1142/S1793830922501014
       
  • LCD matrix product codes with an application

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      Authors: Sanjit Bhowmick, Satya Bagchi, Ramakrishna Bandi
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Matrix product (MP) codes over a finite field [math], where [math] a prime power, were first introduced by Blackmore and Norton [MP codes over [math], Appl. Algebra Engrg. Comm. Comput. 12 (2001) 477–500]. This paper investigates linear complementary dual (LCD) MP codes over finite commutative Frobenius rings. We derive a necessary and sufficient condition for an MP code to have an LCD. We provide some efficient constructions of LCD MP codes. Finally, we have shown an application on cryptography of LCD codes.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-05-20T07:00:00Z
      DOI: 10.1142/S179383092250104X
       
  • The adjacency spectrum and metric dimension of an induced subgraph of
           comaximal graph of [math]

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      Authors: Subarsha Banerjee
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a commutative ring with unity, and let [math] denote the comaximal graph of [math]. The comaximal graph [math] has vertex set as [math], and any two distinct vertices [math] of [math] are adjacent if [math]. Let [math] denote the induced subgraph of [math] on the set of all nonzero non-unit elements of [math], and any two distinct vertices [math] of [math] are adjacent if [math]. In this paper, we study the graphical structure as well the adjacency spectrum of [math], where [math] is a non-prime positive integer, and [math] is the ring of integers modulo [math]. We show that for a given non-prime positive integer [math] with [math] number of positive proper divisors, the eigenvalues of [math] are [math] with multiplicity [math], and remaining eigenvalues are contained in the spectrum of a symmetric [math] matrix. We further calculate the rank and nullity of [math]. We also determine all the eigenvalues of [math] whenever [math] is a bipartite graph. Finally, apart from determining certain structural properties of [math], we conclude the paper by determining the metric dimension of [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-05-13T07:00:00Z
      DOI: 10.1142/S1793830922500938
       
  • The size multipartite Ramsey numbers [math]

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      Authors: Yaser Rowshan, Mostafa Gholami
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Assume that [math] is a complete, and multipartite graph consisting of [math] partite sets and [math] vertices in each partite set. For given graphs [math], the multipartite Ramsey number (M-R-number) [math], is the smallest integer [math], such that for any [math]-edge-coloring [math] of the edges of [math], [math] contains a monochromatic copy of [math] for at least one [math]. The size of M-R-number [math] for [math], the size of M-R-number [math] for [math] and [math], and the size of M-R-number [math] for [math] and [math] have been computed in several papers up to now. In this paper, we determine some lower bounds for the M-R-number [math] for each [math], and some values of M-R-number [math] for some [math], and each [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-05-13T07:00:00Z
      DOI: 10.1142/S1793830922500999
       
  • Complexity aspects of restrained Roman domination in graphs

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      Authors: Padamutham Chakradhar
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      For a simple, undirected graph [math], a restrained Roman dominating function (rRDF) [math] has the property that, every vertex [math] with [math] is adjacent to at least one vertex [math] for which [math] and at least one vertex [math] for which [math]. The weight of an rRDF is the sum [math]. The minimum weight of an rRDF is called the restrained Roman domination number (rRDN) and is denoted by [math]. We show that restrained Roman domination and domination problems are not equivalent in computational complexity aspects. Next, we show that the problem of deciding if [math] has an rRDF of weight at most [math] for chordal and bipartite graphs is NP-complete. Finally, we show that rRDN is determined in linear time for bounded treewidth graphs and threshold graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-05-10T07:00:00Z
      DOI: 10.1142/S1793830922500963
       
  • Some results on majority bad number

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      Authors: I. Sahul Hamid, S. Anandha Prabhavathy
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      A two-valued function [math] defined on the vertices of a graph [math] is a majority bad dominating function (MBDF), if the sum of its function values over at least half the closed neighborhoods is at most one. That is, for at least half the vertices [math], [math], where [math] consists of [math] and every vertex adjacent to [math]. The majority bad domination number of a graph [math], is denoted by [math], and is defined as [math]. In this paper, we determine some results on majority bad number.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-05-10T07:00:00Z
      DOI: 10.1142/S1793830922500987
       
  • The restrained double geodetic number of a graph

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      Authors: A. P. Santhakumaran, K. Ganesamoorthy
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      For a connected graph [math] of order at least two, a double geodetic set [math] of a graph [math] is a restrained double geodetic set if either [math] or the subgraph induced by [math] has no isolated vertices. The minimum cardinality of a restrained double geodetic set of [math] is the restrained double geodetic number of [math] and is denoted by [math]. The restrained double geodetic number of some standard graphs is determined. It is proved that for a nontrivial connected graph [math] [math] if and only if [math]. It is shown that for any three positive integers [math] with [math], there is a connected graph [math] with [math], [math] and [math], where [math] is the geodetic number and [math] is the restrained geodetic number of a graph [math]. It is also shown that for every pair [math], [math] of positive integers with [math], there is a connected graph [math] with [math] and [math], where [math] is the double geodetic number of a graph [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-05-10T07:00:00Z
      DOI: 10.1142/S1793830922501002
       
  • Maximum independent sets in a proper monograph determined through a
           signature

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      Authors: S. M. Hegde, Y. M. Saumya
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a non-empty, finite graph. If the vertices of [math] can be bijectively labeled by a set [math] of positive distinct real numbers with two vertices being adjacent if and only if the positive difference of the corresponding labels is in [math], then [math] is called a proper monograph. The set [math] is called the signature of [math] and denoted as [math]. Not all proper monographs have the property that a set of idle vertices can be bijectively mapped to the maximum independent sets. As a result, in this paper, we present the proper monograph labelings of several classes of graphs that satisfy the property mentioned above. We present the proper monograph labelings of graphs such as cycles, [math], cycles with paths attached to one or more vertices, and Cycles with an irreducible tree attached to one or more vertices.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-05-05T07:00:00Z
      DOI: 10.1142/S1793830922500926
       
  • Linear recurrent cryptography: Golden-like cryptography for higher order
           linear recurrences

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      Authors: Sergiy Koshkin, Daniel Rodriguez
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      We develop matrix cryptography based on linear recurrent sequences of any order that allows securing encryption against brute force and chosen plaintext attacks. In particular, we solve the problem of generalizing error detection and correction algorithms of golden cryptography previously known only for recurrences of a special form. They are based on proving the checking relations (inequalities satisfied by the ciphertext) under the condition that the analog of the golden [math]-matrix has the strong Perron–Frobenius property. These algorithms are proved to be especially efficient when the characteristic polynomial of the recurrence is a Pisot polynomial. Finally, we outline algorithms for generating recurrences that satisfy our conditions.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-05-05T07:00:00Z
      DOI: 10.1142/S179383092250094X
       
  • Minimal instances with no weakly stable matching for three-sided problem
           with cyclic incomplete preferences

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      Authors: Eduard Yu. Lerner, Regina E. Lerner
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Given [math] men, [math] women, and [math] dogs, each man has an incomplete preference list of women, each woman has an incomplete preference list of dogs, and each dog has an incomplete preference list of men. We understand a family as a triple consisting of one man, one woman, and one dog such that the dog belongs to the preference list of the woman, who, in turn, belongs to the preference list of the man, while the latter belongs to the preference list of the dog. We understand a matching as a collection of nonintersecting families (some agents, possibly, remain single). A matching is said to be nonstable, if one can find a man, a woman, and a dog who do not live together currently but each of them would become “happier” if they do. Otherwise, the matching is said to be stable (a weakly stable matching). We give an example of this problem for [math] where no stable matching exists. Moreover, we prove the absence of such an example for [math]. Such an example was known earlier only for [math] [P. Biró and E. McDermid, Three-sided stable matchings with cyclic preferences, Algorithmica 58 (2010) 5–18]. The constructed examples also allow one to halve the size of the recently constructed analogous example for complete preference lists [C.-K. Lam and C.G. Plaxton, On the existence of three-dimensional stable matchings with cyclic preferences, in Algorithmic Game Theory, Lecture Notes in Computer Science, Vol. 11801 (Springer, 2019), pp. 329–342].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-05-05T07:00:00Z
      DOI: 10.1142/S1793830922500951
       
  • An instance-based algorithm for deciding the bias of a coin

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      Authors: Luís Fernando Schultz Xavier da Silveira, Michiel Smid
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] and [math] be real numbers, and let [math] be a coin that comes up heads with an unknown probability [math], such that [math]. We present an algorithm that, on input [math], [math], and [math], decides, with probability at least [math], whether [math] or [math]. The expected number of coin flips made by this algorithm is [math], where [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-05-05T07:00:00Z
      DOI: 10.1142/S1793830922500975
       
  • Complete classification of cyclic codes of length [math] over [math]

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      Authors: Brahim Boudine, Jamal Laaouine, Mohammed Elhassani Charkani
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      In this paper, we use a method inspired by the valuation theory to classify completely cyclic codes of length [math] over [math]. Then, we compute their separation parameters which was useful to compute the Hamming distance in [8].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-29T07:00:00Z
      DOI: 10.1142/S1793830922500914
       
  • Secure equitability in graphs

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      Authors: L. Muthusubramanian, R. Sundareswaran, V. Swaminathan
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      In secure domination [A. P. Burger, M. A. Henning and J. H. Van Vuuren, Vertex covers and secure domination in graphs, Quaest Math. 31 (2008) 163–171; E. J. Cockayne, Irredundance, secure domination and maximum degree in trees, Discrete Math. 307(1) (2007) 12–17; E. J. Cockayne, O. Favaron and C. M. Mynhardt, Secure domination, weak Roman domination and forbidden subgraph, Bull. Inst. Combin. Appl. 39 (2003) 87–100; C. M. Mynhardt, H. C. Swart and E. Ungerer, Excellent trees and secure domination, Util. Math. 67 (2005) 255–267], a vertex outside has the chance of coming inside the dominating set by replacing an element of the set without affecting domination. This idea is combined with equitability. Secure equitable dominating set is introduced and studied. Other concepts like independence and rigid security are also studied in this paper.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-27T07:00:00Z
      DOI: 10.1142/S1793830922500811
       
  • An extended study of [math]-restricted edge connectivity: Another approach
           to Tait’s coloring theorem

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      Authors: G Suresh Singh, Athira Chandran
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      For a graph [math], an edge connectivity [math] is the minimum number of edges whose removal disconnects [math]. In this paper, we define property restricted edge connectivity. Then we appraise its particular case, more precisely [math]-restricted edge connectivity. Some of the basic properties of [math]-restricted edge connectivity are considered. We also discuss how [math]-restricted edge connectivity associates with graph coloring. In particular, we try to study how [math]-restricted edge connectivity relates with Tait’s coloring theorem and thereby the famous Four-color conjecture.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-27T07:00:00Z
      DOI: 10.1142/S1793830922500896
       
  • Hardness of uncertain segment cover, contiguous SAT and visibility with
           uncertain obstacles

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      Authors: Sharareh Alipour, Salman Parsa
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      In this paper, we prove that the uncertain segment cover problem is NP-hard. The uncertain segment cover problem, which appears in solving the question of visibility of a segment in the plane from a given point in the presence of uncertain obstacles, asks if a given interval can be covered by a collection of uncertain sub-intervals having two possible positions. This is done by showing that this problem is equivalent to a special version of the SAT problem that we will call contiguous SAT. In a contiguous SAT problem a CNF formula with a given ordering on its clauses is given such that any literal appears contiguously. We prove that contiguous SAT problem is NP-hard and as a consequence it follows that the uncertain segment cover problem is NP-hard. The approximation solution of this problem and its hardness are also studied.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-22T07:00:00Z
      DOI: 10.1142/S179383092250063X
       
  • Algorithmic aspects of domination number in nano topology induced by graph

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      Authors: V. Sutha Devi, M. Lellis Thivagar, R. Sundareswaran
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The basic intention of this paper is to impart the importance of Nano topology induced by graph. Nano topology induced by graph paves us a method to find the well-known parameter of a graph, namely its domination number as well as all the possible dominating sets of a graph. In general, each paper, depending upon the author’s axe (or the pen), has its own point of emphasis. Accordingly, in this paper, the computational and algorithmic aspects of graph are emphasized. By experience, we know that to solve a problem using graph theory leads to a large graph virtually impossible to analyze without the aid of a computer. Hence, to simplify the problem we have used a Java program code that suits even for all graphs of finite number of vertices. We have made an attempt to find the proper location of guards and minimize the number of guards to observe all the warning lights in a nuclear power plant using such a Java program code.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-22T07:00:00Z
      DOI: 10.1142/S1793830922500823
       
  • Approaches that output infinitely many graphs with small local antimagic
           chromatic number

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      Authors: Gee-Choon Lau, Jianxi Li, Wai-Chee Shiu
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      An edge labeling of a connected graph [math] is said to be local antimagic if it is a bijection [math] such that for any pair of adjacent vertices [math] and [math], [math], where the induced vertex label [math], with [math] ranging over all the edges incident to [math]. The local antimagic chromatic number of [math], denoted by [math], is the minimum number of distinct induced vertex labels over all local antimagic labelings of [math]. In this paper, we show the existence of infinitely many bipartite and tripartite graphs with [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-18T07:00:00Z
      DOI: 10.1142/S1793830922500793
       
  • Global dominating broadcast in graphs

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      Authors: Ibrahim Boufelgha, Moussa Ahmia
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      A broadcast on a graph [math] is a function [math] such that for each [math], where [math] denotes the diameter of [math] and [math] denotes the eccentricity of [math]. The cost of a broadcast is the value [math]. In this paper, we define and study a new invariant of broadcasts in graphs, which is global dominating broadcast. A dominating broadcast [math] of a graph [math] is a global dominating broadcast if [math] is also a dominating broadcast of [math] the complement of [math]. We begin by determining the global broadcast domination number of bipartite graphs, paths, cycles, grid graphs and trees. Then we establish lower and upper bounds on the global broadcast domination number of a graph. Finally, we establish relationships between the global broadcast domination number and other parameters.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-18T07:00:00Z
      DOI: 10.1142/S1793830922500835
       
  • Computing vertex resolvability of some regular planar graphs

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      Authors: Sunny Kumar Sharma, Vijay Kumar Bhat
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a connected graph of order [math]. An ordered subset [math] of vertices in [math] is said to be a resolving set for [math], if all the vertices of [math] are uniquely determined by the vector of distances to the vertices in [math]. The metric dimension of [math] is the minimum cardinality of a resolving set [math] and that resolving set is the metric basis for [math]. In this paper, we show that the metric dimension is three for a family of a three-regular convex polytope.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-18T07:00:00Z
      DOI: 10.1142/S1793830922500860
       
  • Spectrum of corona products based on splitting graphs

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      Authors: Ann Susa Thomas, Sunny Joseph Kalayathankal, Joseph Varghese Kureethara
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a simple undirected graph. Three new corona products of graphs based on splitting graph of [math] are defined. The adjacency spectra of the three new graphs based on splitting graph of [math] are determined. The number of spanning trees and the Kirchoff index of the new graphs are determined using their nonzero Laplacian eigenvalues.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-18T07:00:00Z
      DOI: 10.1142/S1793830922500872
       
  • On weak metric dimension of digraphs

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      Authors: Min Feng, Kaishun Wang, Yuefeng Yang
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Using the two-way distance, we introduce the concept of the weak metric dimension of a strongly connected digraph [math]. We first establish lower and upper bounds for the number of arcs in [math] by using the diameter and weak metric dimension of [math], and characterize all digraphs attaining the lower or upper bound. Then we study a digraph with weak metric dimension [math] and classify all vertex-transitive digraphs having weak metric dimension [math]. Finally, all digraphs of order [math] with weak metric dimension [math] or [math] are determined.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-18T07:00:00Z
      DOI: 10.1142/S1793830922500884
       
  • On the chromatic number of [math]-free graphs

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      Authors: Weilun Xu, Xia Zhang
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      For a graph [math], [math], [math] represent the clique number and the chromatic number of [math], respectively. A hereditary family [math] of graphs is called [math]-bounded with [math]-binding function [math] if [math] for all [math]. A result of Schiermeyer shows that the class of [math]-free graphs has a [math]-binding function [math] [L. Esperet, L. Lemoine, F. Maffray and G. Morel, The chromatic number of [math]-free graphs, Discrete Math. 313 (2013) 743–754]. In this paper, we prove that the class of [math]-free graphs has a [math]-binding function [math]. For the class of [math]-free graphs, we give a [math]-binding function [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-18T07:00:00Z
      DOI: 10.1142/S1793830922500902
       
  • The local complement metric dimension of graphs

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      Authors: Liliek Susilowati, Siti Istikhomah, Moh. Imam Utoyo, S. Slamin
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The metric dimension of graphs has been extended in some types and variations such as local metric dimension and complement metric dimension of graphs. Merging two concepts is one way of developing the concept of graph theory as a branch of mathematics. These two variations motivated us to construct a new concept of metric dimension so called local complement metric dimension. We apply this new concept to some particular classes of graphs and the corona product of two graphs. We also characterize the local complement metric dimension of graphs with certain properties, namely, bipartite graphs and odd cycle graphs. Furthermore, we discover the local complement metric dimension of the corona product of two particular graphs as well as the corona product of two general graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-12T07:00:00Z
      DOI: 10.1142/S1793830922500732
       
  • New results on quadruple Roman domination in graphs

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      Authors: J. Amjadi, N. Khalili
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be an integer and [math] be a simple graph with vertex set [math]. Let [math] be a function that assigns label from the set [math] to the vertices of a graph [math]. For a vertex [math], the active neighborhood of [math], denoted by [math], is the set of vertices [math] such that [math]. A [math]-RDF is a function [math] satisfying the condition that for any vertex [math] with [math], [math]. The weight of a [math]-RDF is [math]. The [math]-Roman domination number [math] of [math] is the minimum weight of an [math]-RDF on [math]. The case [math] is called quadruple Roman domination number. In this paper, we first establish an upper bound for quadruple Roman domination number of graphs with minimum degree two, and then we derive a Nordhaus–Gaddum bound on the quadruple Roman domination number of graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-12T07:00:00Z
      DOI: 10.1142/S1793830922500781
       
  • Outer independent double Italian domination: Complexity, characterization

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      Authors: R. Jalaei, D. A. Mojdeh
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      An outer independent double Italian dominating function is a double Italian dominating function [math] for which the set of vertices assigned [math] under [math] is independent. The outer independent double Italian domination number [math] is the minimum weight taken over all outer independent double Italian dominating functions of [math]. In this work, we present some contributions to the study of outer independent double Italian domination in graphs. We show that the outer independent double Italian domination number is NP-complete even when restricted to planner graphs with maximum degree at most four. We characterize the families of all connected graphs [math] with [math]. We also investigate the families of all graphs [math] such that [math] and for [math], the graphs with this property are characterized. Finally, we characterize the families of all connected graphs [math] of order [math], for which [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-12T07:00:00Z
      DOI: 10.1142/S1793830922500859
       
  • Vertex fault-tolerant spanners for weighted points in polygonal domains

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      Authors: R. Inkulu, Apurv Singh
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Given a set [math] of [math] points, a weight function [math] to associate a non-negative weight to each point in [math], a positive integer [math], and a real number [math], we devise the following algorithms to compute a [math]-vertex fault-tolerant spanner network [math] for the metric space induced by the weighted points in [math]: (1). When the points in [math] are located in a simple polygon, we present an algorithm to compute [math] with multiplicative stretch [math], and the number of edges in [math] (size of [math]) is [math]. (2) When the points in [math] are located in the free space of a polygonal domain [math] with [math] number of obstacles, we present an algorithm to compute [math] with multiplicative stretch [math] and size [math]. (3) When the points in [math] are located on a polyhedral terrain, we devise an algorithm to compute [math] with multiplicative stretch [math] and size [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-11T07:00:00Z
      DOI: 10.1142/S1793830922500744
       
  • On some formulas in the problem of enumeration of finite labeled
           topologies

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      Authors: Kh. Sh. Al’Dzhabri, V. I. Rodionov
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Among the unsolved problems of enumeration of graphs, one of the most difficult is the problem of enumeration of transitive digraphs, which is equivalent to the problem of enumeration of finite partial orders and is equivalent to the problem of enumeration of finite labeled [math]-topologies. The sequence [math], where [math] is the number of all labeled [math]-topologies defined on an [math]-set, has been studied from different points of view. In the previous work of the second author, a formula was obtained in which the number [math] is represented as a linear combination of numbers [math] (where the sequences [math] are compositions of the number [math]). Recurrent relations between individual numbers [math] were obtained. In this paper, new recursive formulas between separate numbers [math] are obtained.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-11T07:00:00Z
      DOI: 10.1142/S1793830922500756
       
  • Total dominator coloring number of middle graphs

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      Authors: Farshad Kazemnejad, Behnaz Pahlavsay, Elisa Palezzato, Michele Torielli
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      A total dominator coloring of a graph [math] is a proper coloring of [math] in which each vertex of the graph is adjacent to every vertex of some color class. The total dominator chromatic number of a graph is the minimum number of color classes in a total dominator coloring. In this paper, we study the total dominator coloring on middle graphs by giving several bounds for the case of general graphs and trees. Moreover, we calculate explicitly the total dominator chromatic number of the middle graph of several known families of graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-11T07:00:00Z
      DOI: 10.1142/S1793830922500768
       
  • On fourth leap Zagreb index of graphs

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      Authors: Ammar Alsinai, Anwar Saleh, Hanan Ahmed, Lakshmi Narayan Mishra, N. D. Soner
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      In this research work, we introduce a new version of leap Zagreb index called fourth leap Zagreb index. Mathematical properties and exact values for some standard classes of graphs for this new topological index are obtained. Also, the upper bounds are established. The values of this index for some graph operations containing the Cartesian product, Join and Composition are found.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-11T07:00:00Z
      DOI: 10.1142/S179383092250077X
       
  • Progress on fault-tolerant locating-dominating sets

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      Authors: Devin C. Jean, Suk J. Seo
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      A locating-dominating set is a subset of vertices representing “detectors” in a graph [math] which can locate an “intruder” given that each detector covers its closed neighborhood and can distinguish its own location from its neighbors. We explore a fault-tolerant variant of locating-dominating sets, called error-detecting locating-dominating (DET:LD) sets, which can tolerate one false negative. The concept of DET:LD sets was originally introduced in 2002, along with several properties in various classes of graphs; we extend this work by fully characterizing DET:LD sets for general graphs and establishing existence criteria. We prove that the problem of determining the minimum density of a DET:LD set in arbitrary graphs is NP-complete. Additionally, we determine that the minimum density in cubic graphs is at least [math], and we show an infinite family of cubic graphs achieving this density.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-11T07:00:00Z
      DOI: 10.1142/S179383092250080X
       
  • 2-Distance coloring of planar graphs without triangles and intersecting
           4-cycles

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      Authors: Yuehua Bu, Zewei Zhang, Hongguo Zhu
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The [math]-2-distance coloring of graph [math] is a mapping [math] if any two vertices at distance at most two from each other get different colors. The 2-distance chromatic number is the smallest integer [math] such that [math] has a [math]-2-distance coloring, denoted by [math]. In this paper, we prove that every planar graph [math] without 3-cycles and intersecting 4-cycles and [math] has [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-04-11T07:00:00Z
      DOI: 10.1142/S1793830922500847
       
  • [math]-additive cyclic and constacyclic codes and MDSS codes

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      Authors: Arazgol Ghajari, Kazem Khashyarmanesh, Taher Abualrub, Irfan Siap
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      In this paper, we will study the structure of [math]-additive codes where [math] is the well-known ring of 4 elements and [math] is the ring given by [math], where [math], [math] and [math]. We will classify all maximum distance separable codes with respect to the Singleton bound (MDSS) over [math] Then we will focus on [math]-additive cyclic and constacyclic codes. We will find a unique set of generator polynomials for these codes and determine minimum spanning sets for them. We will also find the generator polynomials for the dual of any [math]-additive cyclic or constacyclic code.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-03-28T07:00:00Z
      DOI: 10.1142/S1793830922500665
       
  • Type-II polyadic constacyclic codes over finite fields

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      Authors: Somphong Jitman, San Ling, Jareena Tharnnukhroh
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Polyadic constacyclic codes over finite fields have been of interest due to their nice algebraic structures, good parameters, and wide applications. Recently, the study of Type-I [math]-adic constacyclic codes over finite fields has been established. In this paper, a family of Type-II [math]-adic constacyclic codes is investigated. The existence of such codes is determined using the length of orbits in a suitable group action. A necessary condition and a sufficient condition for a positive integer [math] to be a multiplier of a Type-II [math]-adic constacyclic code are determined. Subsequently, for a given positive integer [math], a necessary condition and a sufficient condition for the existence of Type-II [math]-adic constacyclic codes are derived. In many cases, these conditions become both necessary and sufficient. For the other cases, determining necessary and sufficient conditions is equivalent to the discrete logarithm problem which is considered to be computationally intractable. Some special cases are investigated together with examples of Type-II polyadic constacyclic codes with good parameters.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-03-28T07:00:00Z
      DOI: 10.1142/S1793830922500720
       
  • On normalized Laplacian eigenvalues of power graphs associated to finite
           cyclic groups

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      Authors: Bilal A. Rather, S. Pirzada, T. A. Chishti, Ahmad M. Alghamdi
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      For a simple connected graph [math] of order [math], the normalized Laplacian is a square matrix of order [math], defined as [math], where [math] is the diagonal matrix whose [math]-th diagonal entry is [math]. In this paper, we find the normalized Laplacian eigenvalues of the joined union of regular graphs in terms of the adjacency eigenvalues and the eigenvalues of quotient matrix associated with graph [math]. For a finite group [math], the power graph [math] of a group [math] is defined as the simple graph in which two distinct vertices are joined by an edge if and only if one is the power of the other. As a consequence of the joined union of graphs, we investigate the normalized Laplacian eigenvalues of the power graphs of the finite cyclic group [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-03-21T07:00:00Z
      DOI: 10.1142/S1793830922500707
       
  • Some results on generalized self-complementary graphs

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      Authors: H. J. Gowtham, Shankar N. Upadhyay, Sabitha D’Souza, Pradeep G. Bhat
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a partition of vertex set [math] of order [math] of a graph [math]. The [math]-complement of [math] denoted by [math] is defined as for all [math] and [math] in [math], [math], remove the edges between [math] and [math] in [math] and add the edges between [math] and [math] which are not in [math]. The graph [math] is called [math]-self-complementary if [math]. For a graph [math], [math]-complement of [math] denoted by [math] is defined as for each [math] remove the edges of [math] inside [math] and add the edges of [math] by joining the vertices of [math]. The graph [math] is called [math]-self-complementary if [math] for some partition [math] of order [math]. In this paper, we determine generalized self-complementary graphs of forest, double star and unicyclic graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-03-12T08:00:00Z
      DOI: 10.1142/S1793830922500653
       
  • Wiener index of sum of shadowgraphs

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      Authors: Shanu Goyal, Dilip Jain, Vishnu Narayan Mishra
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The Wiener index of a graph [math], denoted by [math], is defined as W(G) =∑u≠vd(u,v), where the sum is taken through all unordered pairs of vertices of [math] and [math] is distance between two vertices [math] and [math] of [math]. Let [math] and [math] be two graphs. For a graph [math], let [math] be a copy of [math] and [math]. The [math]-sum [math] is a graph with the set of vertices [math] and two vertices [math] and [math] of [math] are adjacent if and only if [math] or [math], where [math] be one of the shadowgraph [math] or closed shadowgraph [math]. In this paper, we reported the Wiener index of these graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-03-12T08:00:00Z
      DOI: 10.1142/S1793830922500689
       
  • Indicated coloring of the Mycielskian of some families of graphs

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      Authors: P. Francis
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Indicated coloring is a graph coloring game in which two players collectively color the vertices of a graph in the following way. In each round, the first player (Ann) selects a vertex, and then the second player (Ben) colors it properly, using a fixed set of colors. The goal of Ann is to achieve a proper coloring of the whole graph, while Ben is trying to prevent the realization of this project. The smallest number of colors necessary for Ann to win the game on a graph [math] (regardless of Ben’s strategy) is called the indicated chromatic number of [math], denoted by [math]. In this paper, we examine whether the Mycielskian of [math], [math], is [math]-indicated colorable for all [math], whenever [math] is [math]-indicated colorable for all [math]. In this direction, we prove that the Mycielskian of the bipartite graphs, complete multipartite graphs, [math]-free graphs, [math]-free graphs, [math]-free graphs and [math]-free graphs are [math]-indicated colorable for all [math] greater than or equal to the indicated chromatic number of the corresponding graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-03-12T08:00:00Z
      DOI: 10.1142/S1793830922500690
       
  • The generalized path matrix and energy

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      Authors: Pengli Lu, Rui Luan
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      We define the path Laplacian matrix and the path signless Laplacian matrix of a simple connected graph [math] as [math] and [math], respectively, where [math] is the path matrix and [math] is the diagonal matrix of the vertex transmissions. The generalized path matrix is [math], for [math] and [math] are the eigenvalues of [math]. The generalized path energy can be expressed as [math], where [math] is the path Wiener index of [math]. We give basic properties of generalized path matrix [math]. Also, some upper and lower bounds of the generalized path energy of some graphs are studied.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-03-10T08:00:00Z
      DOI: 10.1142/S1793830922500719
       
  • The second-minimum and second-maximum values of exponential Zagreb indices
           among trees

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      Authors: Lu Yang, Yan Zhu
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Exponential of the first Zagreb index and the second Zagreb index of a graph [math] are defined as [math] and [math], where [math] denotes the set of edges and [math] denotes the degree of a vertex [math]. The extremal trees of these two indices among trees have been determined in previous studies. In this paper, we give the second-minimum and the second-maximum values of [math] and [math] among trees.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-03-08T08:00:00Z
      DOI: 10.1142/S1793830922500641
       
  • Embedding and the rotational dimension of a graph containing a clique

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      Authors: Takumi Gomyou
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The rotational dimension is a minor-monotone graph invariant related to the dimension of a Euclidean space containing a spectral embedding corresponding to the first nonzero eigenvalue of the graph Laplacian, which is introduced by Göring, Helmberg and Wappler. In this paper, we study rotational dimensions of graphs which contain large complete graphs. The complete graph is characterized by its rotational dimension. It will be obtained that a chordal graph may be made large while keeping the rotational dimension constant.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-02-25T08:00:00Z
      DOI: 10.1142/S1793830922500616
       
  • Corona product of signed graphs and its application to modeling signed
           networks

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      Authors: Bibhas Adhikari, Amrik Singh, Sandeep Kumar Yadav
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The notion of corona of two graphs was introduced by Frucht and Harary in 1970. In this paper, we generalize their definition of corona product of two graphs and introduce corona product of two signed graphs by utilizing the framework of marked graphs, which was introduced by Beineke and Harary in 1978. We study structural and spectral properties of corona product of signed graphs. Further, we define signed corona graphs by considering corona product of a fixed small signed graph with itself iteratively, and we call the small graph as the seed graph for the corresponding corona product graphs. Signed corona graphs can be employed as a signed network generative model for large growing signed networks. We study structural properties of corona graphs that include statistics of signed links, all types of signed triangles and degree distribution. Besides we analyze algebraic conflict of signed corona graphs generated by specially structured seed graphs. Finally, we show that a suitable choice of a seed graph can produce corona graphs which preserve properties of real signed networks.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-02-25T08:00:00Z
      DOI: 10.1142/S1793830922500628
       
  • Partially balanced incomplete block (PBIB)-designs associated with
           geodetic sets in graphs

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      Authors: Medha Itagi Huilgol, M. D. Vidya
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      A [math]-design over regular graph [math] of degree [math] is an ordered pair [math], where [math] and [math] is the set of geodetic sets in [math] called blocks such that two vertices [math] and [math] which are [math] associates occur together in [math] blocks, the numbers [math] being independent of the choice of the pair [math] and [math]. In this paper, we obtain Partially Balanced Incomplete Block (PBIB)-designs arising from geodetic sets in some classes of graphs. Also, we give a complete list of PBIB-designs with respect to the geodetic sets for cubic graphs of order at most [math]. The discussion of non-existence of some designs corresponding to geodetic sets from certain graphs concludes the paper.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-02-22T08:00:00Z
      DOI: 10.1142/S1793830922500598
       
  • A note on Hamiltonian cycles in planar graphs

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      Authors: Martin Kreh
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Unlike the problem of finding Eulerian cycles, the problem of deciding whether a given graph has a Hamiltonian cycle is NP-complete, even when restricting to planar graphs. There are however some criteria that can be used in special cases. One of them can be derived by Grinberg’s theorem. In this note, we give some more (slightly more general) criteria derived from Grinberg’s theorem to show that a graph does not have a Hamiltonian cycle.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-02-17T08:00:00Z
      DOI: 10.1142/S1793830922500604
       
  • Topological indices of the wreath product of graphs

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      Authors: Yongqin Zhang, Jianfeng Wang, Maurizio Brunetti
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Topological indices, i.e., numerical invariants suitably associated to graphs and only depending upon their isomorphism type, have important applications in Chemistry. Their computation constitutes an important branch of Chemical Graph Theory. In this paper, we focus on some degree and distance-based invariants related to the Zagreb indices, the Szeged index and the Wiener index, namely, the F-index, the vertex PI index and the hyper-Wiener index. In particular, we find the formulæ to compute these topological invariants for wreath product of graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-02-11T08:00:00Z
      DOI: 10.1142/S1793830922500562
       
  • Total outer connected vertex-edge domination

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      Authors: B. Senthilkumar, H. Naresh Kumar, Y. B. Venkatakrishnan
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      A vertex [math] of a graph is said to [math]-[math] dominate every edge incident with [math], as well as every edge incident to vertices adjacent to [math]. A subset [math] is a total outer connected vertex-edge dominating set of a graph [math] if every edge in [math] is [math]-[math] dominated by a vertex in [math], the subgraph induced by [math] has no isolated vertices and the subgraph induced by [math] is connected. We initiate the study of total outer connected vertex-edge domination in graphs. We show that the decision problem for total outer-connected vertex-edge domination problem is [math]-Complete even for bipartite graphs. We prove that for every tree of order [math] with [math] leaves, [math] and characterize the trees attaining the lower bound. We also study the effect of edge removal, edge addition and edge subdivision on total outer connected vertex-edge domination number of a graph.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-02-11T08:00:00Z
      DOI: 10.1142/S1793830922500574
       
  • The Tutte polynomial of a class of compound graphs and its applications

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      Authors: Hanlin Chen
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The Tutte polynomial, a considerable generalization of the chromatic polynomial, associated with a graph is a classical bivariate polynomial, which gives various interesting information about the graph structure. In this paper, we first present a formula for the Tutte polynomial of a class of special compound graphs. Then as applications, we obtain the Tutte polynomials of some complex network models in the context of statistical physics and the Tutte polynomials of some chemical polycyclic graphs. Moreover, explicit expressions of the number of spanning trees for these considered graphs are determined, respectively.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-02-11T08:00:00Z
      DOI: 10.1142/S1793830922500586
       
  • Fission: Practical algorithms for computing minimum balanced node
           separators

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      Authors: Johannes Blum, Ruoying Li, Sabine Storandt
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Given an undirected graph, a balanced node separator is a set of nodes whose removal splits the graph into connected components of limited size. Balanced node separators are used for graph partitioning, for the construction of graph data structures, and for measuring network reliability. It is NP-hard to decide whether a graph has a balanced node separator of size at most [math]. Therefore, practical algorithms typically try to find small separators in a heuristic fashion. In this paper, we present a branching algorithm that for a given value [math] either outputs a balanced node separator of size at most [math] or certifies that [math] is a valid lower bound. Using this algorithm iteratively for growing values of [math] allows us to find a minimum balanced node separator. To make this algorithm scalable to real-world (road) networks of considerable size, we first describe pruning rules to reduce the graph size without affecting the minimum balanced separator size. In addition, we prove several structural properties of minimum balanced node separators which are then used to reduce the branching factor and search depth of our algorithm. We experimentally demonstrate the applicability of our algorithm to graphs with thousands of nodes and edges. We showcase the usefulness of having minimum balanced separators for judging the quality of existing heuristics, for improving preprocessing-based route planning techniques on road networks, and for lower bounding important graph parameters. Finally, we discuss how our ideas and methods can also be leveraged to accelerate the heuristic computation of balanced node separators.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-01-22T08:00:00Z
      DOI: 10.1142/S1793830922500483
       
  • On 3-degree 4-chordal graphs

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      Authors: Devarshi Aggarwal, R. Mahendra Kumar, N. Sadagopan
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      A graph [math] is a 3-degree 4-chordal graph if every cycle of length at least five has a chord and the degree of each vertex is at most three. In this paper, we investigate the structure of 3-degree 4-chordal graphs, which is a subclass of 3-degree graphs. We present a structural characterization based on minimal vertex separators and bi-connected components. Many classical problems are known to be NP-complete for 3-degree graphs, and 3-degree 4-chordal graphs are a nontrivial subclass of 3-degree graphs. Using our structural results, we present polynomial-time algorithms for many classical problems which are grouped into (i) subset problems (vertex cover and its variants, feedback vertex set, Steiner tree), (ii) Hamiltonicity and its variants, (iii) graph embedding problems (treewidth, minimum fill-in), and (iv) Coloring problems(rainbow coloring).
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-01-22T08:00:00Z
      DOI: 10.1142/S1793830922500537
       
  • Eccentric connectivity coindex of bipartite graphs

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      Authors: Tomáš Vetrík, Mesfin Masre, Selvaraj Balachandran
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The eccentric connectivity coindex of a graph [math] is defined as [math], where [math] is the vertex set of [math], [math] is the edge set of [math], [math] is the eccentricity of [math] and [math] is the degree of [math] in [math]. We present lower bounds on the eccentric connectivity coindex for bipartite graphs of given order and vertex connectivity, order and matching number, order and odd diameter. The extremal graphs are presented as well. To the best of our knowledge, our extremal graphs of given order and vertex connectivity are not extremal graphs for any other research problem in graph theory.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-01-19T08:00:00Z
      DOI: 10.1142/S1793830922500549
       
  • [math]-induced-paired dominating graphs of paths and cycles

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      Authors: Saharath Sanguanpong, Nantapath Trakultraipruk
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      For any graph [math], a nonempty subset [math] of [math] is called an induced-paired dominating set if every vertex in [math] is adjacent to some vertex in [math], and the induced subgraph [math] contains only independent edges. An induced-paired dominating set of [math] with minimum number of vertices is also called a [math]-set. We define the [math]-induced paired dominating graph of [math], denoted by [math], to be the graph whose vertex set consists of all [math]-sets, and two [math]-sets are adjacent in [math] if they are different from each other by only one vertex. In this paper, we exhibit all [math]-induced-paired dominating graphs of paths and cycles.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-01-15T08:00:00Z
      DOI: 10.1142/S1793830922500471
       
  • Pancyclic zero divisor graph over the ring [math]

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      Authors: Ravindra Kumar, Om Prakash
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be the zero divisor graph over the ring [math]. In this paper, we study pancyclic properties of [math] and [math], respectively, for different [math]. Also, we prove some results in which [math] and [math] are pancyclic for different values of [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-01-15T08:00:00Z
      DOI: 10.1142/S1793830922500495
       
  • [math]-Efficient domination: Algorithmic perspective

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      Authors: Mohsen Alambardar Meybodi
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      A set [math] of a graph [math] is called an efficient dominating set of [math] if every vertex [math] has exactly one neighbor in [math], in other words, the vertex set [math] is partitioned to some circles with radius one such that the vertices in [math] are the centers of partitions. A generalization of this concept, introduced by Chellali et al. [k-Efficient partitions of graphs, Commun. Comb. Optim. 4 (2019) 109–122], is called [math]-efficient dominating set that briefly partitions the vertices of graph with different radiuses. It leads to a partition set [math] such that each [math] consists a center vertex [math] and all the vertices in distance [math], where [math]. In other words, there exist the dominators with various dominating powers. The problem of finding minimum set [math] is called the minimum [math]-efficient domination problem. Given a positive integer [math] and a graph [math], the [math]-efficient Domination Decision problem is to decide whether [math] has a [math]-efficient dominating set of cardinality at most [math]. The [math]-efficient Domination Decision problem is known to be NP-complete even for bipartite graphs [M. Chellali, T. W. Haynes and S. Hedetniemi, k-Efficient partitions of graphs, Commun. Comb. Optim. 4 (2019) 109–122]. Clearly, every graph has a [math]-efficient dominating set but it is not correct for efficient dominating set. In this paper, we study the following: [math]-efficient domination problem set is NP-complete even in chordal graphs. A polynomial-time algorithm for [math]-efficient domination in trees. [math]-efficient domination on sparse graphs from the parametrized complexity perspective. In particular, we show that it is [math]-hard on d-degenerate graphs while the original dominating set has Fixed Parameter Tractable (FPT) algorithm on d-degenerate graphs. [math]-efficient domination on nowhere-dense graphs is FPT.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-01-12T08:00:00Z
      DOI: 10.1142/S1793830922500513
       
  • Minimum constraint removal problem for line segments is NP-hard

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      Authors: Bahram Sadeghi Bigham
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      In the minimum constraint removal ([math]), there is no feasible path to move from a starting point towards the goal, and the minimum constraints should be removed in order to find a collision-free path. It has been proved that [math] problem is NP-hard when constraints have arbitrary shapes or even they are in shape of convex polygons. However, it has a simple linear solution when constraints are lines and the problem is open for other cases yet. In this paper, using a reduction from Subset Sum problem, in three steps, we show that the problem is NP-hard for both weighted and unweighted line segments.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-01-12T08:00:00Z
      DOI: 10.1142/S1793830922500550
       
  • On a spanning subgraph of the annihilating-ideal graph of a commutative
           ring

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      Authors: S. Visweswaran
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The rings considered in this paper are commutative with identity which are not integral domains. Let [math] be a ring. Let us denote the set of all annihilating ideals of [math] by [math] and [math] by [math]. With [math], we associate an undirected graph, denoted by [math], whose vertex set is [math] and distinct vertices [math] and [math] are adjacent in this graph if and only if [math] and [math]. The aim of this paper is to study the interplay between the graph-theoretic properties of [math] and the ring-theoretic properties of [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-01-10T08:00:00Z
      DOI: 10.1142/S1793830922500501
       
  • On the variants of first KCD energy

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      Authors: Keerthi G. Mirajkar, Akshata Morajkar
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The variants of first Karnatak College Dharwad energy, in brief, the first [math] energy, namely the first [math] hyperenergeticity, the first [math] borderenergeticity and the first [math] equienergeticity, are defined. These concepts are further studied for complement, line graph and splitting graph of a graph. Lastly, some results on first [math] equienergetic graphs are obtained.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-01-10T08:00:00Z
      DOI: 10.1142/S1793830922500525
       
  • On the double Roman bondage numbers of graphs

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      Authors: N. Jafari Rad, H. R. Maimani, M. Momeni, F. Rahimi Mahid
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      For a graph [math], a double Roman dominating function (DRDF) is a function [math] having the property that if [math] for some vertex [math], then [math] has at least two neighbors assigned [math] under [math] or one neighbor [math] with [math], and if [math] then [math] has at least one neighbor [math] with [math]. The weight of a DRDF [math] is the sum [math]. The minimum weight of a DRDF on a graph [math] is the double Roman domination number of [math] and is denoted by [math]. The double Roman bondage number of [math], denoted by [math], is the minimum cardinality among all edge subsets [math] such that [math]. In this paper, we study the double Roman bondage number in graphs. We determine the double Roman bondage number in several families of graphs, and present several bounds for the double Roman bondage number. We also study the complexity issue of the double Roman bondage number and prove that the decision problem for the double Roman bondage number is NP-hard even when restricted to bipartite graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2022-01-07T08:00:00Z
      DOI: 10.1142/S179383092250046X
       
  • Birecognition of prime graphs, and minimal prime graphs

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      Authors: Houmem Belkhechine, Cherifa Ben Salha, Pierre Ille
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Given a graph [math], a subset [math] of [math] is a module of [math] if for each [math], [math] is adjacent to all the elements of [math] or to none of them. For instance, [math], [math] and [math] ([math]) are the trivial modules of [math]. A graph [math] is prime if [math] and all its modules are trivial. Given a prime graph [math], consider [math] such that [math] is prime. Given a graph [math] such that [math] and [math], [math] and [math] are [math]-similar if for each [math], [math] and [math] are both prime or not. The graph [math] is said to be [math]-birecognizable if every graph, [math]-similar to [math], is prime. We study the graphs [math] that are not [math]-birecognizable, where [math] such that [math] is prime, by using the following notion of a minimal prime graph. Given a prime graph [math], consider [math] such that [math] is prime. Given [math], [math] is [math]-minimal if for each [math] such that [math], [math] is not prime.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-12-28T08:00:00Z
      DOI: 10.1142/S1793830922500380
       
  • 2-Point set domination in separable graphs

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      Authors: Purnima Gupta, Deepti Jain
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      In a graph [math], a set [math] is a [math]-point set dominating set (in short 2-psd set) of [math] if for every subset [math] there exists a nonempty subset [math] containing at most two vertices such that the induced subgraph [math] is connected in [math]. The [math]-point set domination number of [math], denoted by [math], is the minimum cardinality of a 2-psd set of [math]. The main focus of this paper is to find the value of [math] for a separable graph and thereafter computing [math] for some well-known classes of separable graphs. Further we classify the set of all 2-psd sets of a separable graph into six disjoint classes and study the existence of minimum 2-psd sets in each class.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-12-28T08:00:00Z
      DOI: 10.1142/S1793830922500446
       
  • Injective edge-coloring of subcubic graphs

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      Authors: Baya Ferdjallah, Samia Kerdjoudj, André Raspaud
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      An injective edge-coloring [math] of a graph [math] is an edge-coloring such that if [math], [math], and [math] are three consecutive edges in [math] (they are consecutive if they form a path or a cycle of length three), then [math] and [math] receive different colors. The minimum integer [math] such that, [math] has an injective edge-coloring with [math] colors, is called the injective chromatic index of [math] ([math]). This parameter was introduced by Cardoso et al. [Injective coloring of graphs, Filomat 33(19) (2019) 6411–6423, arXiv:1510.02626] motivated by the Packet Radio Network problem. They proved that computing [math] of a graph [math] is NP-hard. We give new upper bounds for this parameter and we present the relationships of the injective edge-coloring with other colorings of graphs. We study the injective edge-coloring of some classes of subcubic graphs. We prove that a subcubic bipartite graph has an injective chromatic index bounded by [math]. We also prove that if [math] is a subcubic graph with maximum average degree less than [math] (respectively, [math]), then [math] admits an injective edge-coloring with at most 4 (respectively, [math]) colors. Moreover, we establish a tight upper bound for subcubic outerplanar graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-12-17T08:00:00Z
      DOI: 10.1142/S1793830922500409
       
  • Strong chromatic index of generalized Jahangir graphs and generalized Helm
           graphs

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      Authors: Vikram Srinivasan Thiru, S. Balaji
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The strong edge coloring of a graph G is a proper edge coloring that assigns a different color to any two edges which are at most two edges apart. The minimum number of color classes that contribute to such a proper coloring is said to be the strong chromatic index of G. This paper defines the strong chromatic index for the generalized Jahangir graphs and the generalized Helm graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-12-17T08:00:00Z
      DOI: 10.1142/S1793830922500458
       
  • Edge-vertex domination in trees

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      Authors: Kijung Kim
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a finite simple graph. A vertex [math] is edge-vertex dominated by an edge [math] if [math] is incident with [math] or [math] is incident with a vertex adjacent to [math]. An edge-vertex dominating set of [math] is a subset [math] such that every vertex of [math] is edge-vertex dominated by an edge of [math]. The edge-vertex domination number [math] is the minimum cardinality of an edge-vertex dominating set of [math]. In this paper, we prove that [math] for every tree [math] of order [math] with [math] leaves, and we characterize the trees attaining each of the bounds.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-12-09T08:00:00Z
      DOI: 10.1142/S1793830922500434
       
  • Computation of diameter, radius and center of permutation graphs

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      Authors: Shaoli Nandi, Sukumar Mondal, Sambhu Charan Barman
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      For a connected graph [math], we use the notation [math] to represent the distance between two node points [math] and [math] and it is the minimum of the lengths of all paths between them. The eccentricity [math] of a node point [math] is considered as the maximum length of all shortest paths starts from [math] to the remaining nodes, i.e., [math]. The diameter of a graph [math], we denote it by [math] and it is the length of the longest shortest path in [math], i.e., [math]. Also, the radius of a graph [math], we denote it by the symbol [math] and it is the least eccentricity of all node points in [math], i.e., [math]. The central vertex/node point [math] of a graph [math] is a node whose eccentricity is same as [math]’s radius, i.e., [math]. The collection of all central nodes of a graph [math] is considered as the center of [math] and it is symbolized by [math], i.e., [math]. A graph may have one or more central vertices. This paper develops an optimal algorithm to compute the diameter, radius and central node (s) of the permutation graph having [math] node points in [math] time. We have also established a tight relation between radius and diameter of permutation graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-12-06T08:00:00Z
      DOI: 10.1142/S1793830922500392
       
  • Crosscap two of class of graphs from commutative rings

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      Authors: S. Karthik, S. N. Meera, K. Selvakumar
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a commutative ring with identity and [math] be the set of all nonzero zero-divisors of [math]. The annihilator graph of commutative ring [math] is the simple undirected graph [math] with vertices [math] and two distinct vertices [math] and [math] are adjacent if and only if [math]. The essential graph of [math] is defined as the graph [math] with the vertex set [math] and two distinct vertices [math] and [math] are adjacent if and only if [math] is an essential ideal. In this paper, we classify all finite commutative rings with identity whose annihilator graph and essential graph have crosscap two.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-12-02T08:00:00Z
      DOI: 10.1142/S1793830922500410
       
  • On-line interval graphs coloring — Modification of the First-Fit
           algorithm and its performance ratio

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      Authors: Bartosz Bieganowski
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      We propose a modification of the First-Fit algorithm in which we forbid the use of the most frequently used color. We provide some lower bound of the performance ratio [math] on the family of interval graphs [math], where [math] denotes the number of used colors by the modified version of the First-Fit algorithm and [math] is the number of vertices in the largest complete subgraph in [math]. We also compare the modification with the usual First-Fit algorithm on some experimental data.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-12-02T08:00:00Z
      DOI: 10.1142/S1793830922500422
       
  • A note on no-free-lunch theorem

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      Authors: Lidong Wu
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The No-Free-Lunch theorem is an interesting and important theoretical result in machine learning. Based on philosophy of No-Free-Lunch theorem, we discuss extensively on the limitation of a data-driven approach in solving NP-hard problems.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-29T08:00:00Z
      DOI: 10.1142/S1793830922500276
       
  • On the domination number of a graph and its block graph

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      Authors: E. Murugan, J. Paulraj Joseph
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a graph. A subset [math] of [math] is called a dominating set of [math] if every vertex not in [math] is adjacent to some vertex in [math] The domination number [math] of [math] is the minimum cardinality taken over all dominating sets of [math] The block graph [math] of a graph [math] is a graph whose vertex set is the set of blocks in [math] and two vertices of [math] are adjacent if and only if the corresponding blocks have a common cut vertex in [math] In this paper, we investigate the lower and upper bounds for the sum of domination number of a graph and its block graph and characterize the extremal graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-27T08:00:00Z
      DOI: 10.1142/S1793830922500331
       
  • Development of algorithm simulating spatial fold change of cell signaling
           for pattern formation in zebrafish

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      Authors: Bilal Gonen, Sai Nikhil Bheemanathini
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Embryos develop robust spatiotemporal patterns by encoding and interpreting biological signals in real time. Developmental patterns often scale with body or tissue size even when total cell number, cell size or growth rate are changed. A striking example of patterning is the segmentation of somites — the precursors of vertebral column. Despite decade-long efforts, how positional information for segmentation is encoded by cell signaling remained elusive. To address this fundamental question, we studied a novel zebrafish tail explant model that recapitulated the scaling of somite sizes with the length of unsegmented tissue in growing intact embryos. This paper provides an algorithm written in MATLAB as well as Python and finally finding a way to write an efficient algorithm to be able to answer the question described above. Information encoding by spatial fold-change of cell signaling is a remarkable strategy that could be utilized for engineering precisely patterned tissues or organs. We also discuss the limitations of simulations performed using MATLAB with performance decreasing with the large data sets. So, we tried to analyze the factors that impacted the performance of the algorithm. Finally, we tried to answer questions regarding the language selection in which a simulation method can be written efficiently.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-24T08:00:00Z
      DOI: 10.1142/S1793830922500082
       
  • The spectrum and metric dimension of Indu–Bala product of graphs

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      Authors: Subarsha Banerjee
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Given a connected graph [math], the distance Laplacian matrix [math] is defined as [math], and the distance signless Laplacian matrix [math] is defined as [math], where [math] is the transmission matrix of [math] and [math] is the distance matrix of [math]. The Indu–Bala product of two graphs [math] and [math], denoted by [math], was introduced in (G. Indulal and R. Balakrishnan, Distance spectrum of Indu–Bala product of graphs, AKCE Int. J. Graph Comb. 13(3) (2016) 230–234). In this paper, we first obtain the distance Laplacian spectrum of [math] in terms of Laplacian spectra of [math] and [math]. We then obtain the distance signless Laplacian spectrum of [math] in terms of signless Laplacian spectra of [math] and [math]. We construct pair of graphs which are distance Laplacian co-spectral as well as pair of graphs which are distance signless Laplacian co-spectral. We further find the metric dimension of [math] in terms of metric dimensions of [math] and [math]. Finally, we provide a problem for future research.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-24T08:00:00Z
      DOI: 10.1142/S1793830922500379
       
  • Bounds on the Steiner–Wiener index of graphs

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      Authors: V. A. Rasila, Ambat Vijayakumar
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a set of vertices of a connected graph [math]. The Steiner distance of [math] is the minimum size among all connected subgraphs of [math] containing the vertices of [math]. The sum of all Steiner distances on sets of size [math] is called the Steiner [math]-Wiener index. We obtain formulae for bounds on the Steiner–Wiener index of graphs in terms of chromatic number, vertex connectivity and independence number. Also, we obtain bounds for 4-cycle free graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-18T08:00:00Z
      DOI: 10.1142/S1793830922500173
       
  • Inductive graph invariants and approximation algorithms

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      Authors: C. R. Subramanian
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      We introduce and study an inductively defined analogue [math] of any increasing graph invariant [math]. An invariant [math] is increasing if [math] whenever [math] is an induced subgraph of [math]. This inductive analogue simultaneously generalizes and unifies known notions like degeneracy, inductive independence number, etc., into a single generic notion. For any given increasing [math], this gets us several new invariants and many of which are also increasing. It is also shown that [math] is the minimum (over all orderings) of a value associated with each ordering. We also explore the possibility of computing [math] (and a corresponding optimal vertex ordering) and identify some pairs [math] for which [math] can be computed efficiently for members of [math]. In particular, it includes graphs of bounded [math] values. Some specific examples (like the class of chordal graphs) have already been studied extensively. We further extend this new notion by (i) allowing vertex weighted graphs, (ii) allowing [math] to take values from a totally ordered universe with a minimum and (iii) allowing the consideration of [math]-neighborhoods for arbitrary but fixed [math]. Such a generalization is employed in designing efficient approximations of some graph optimization problems. Precisely, we obtain efficient algorithms (by generalizing the known algorithm of Ye and Borodin [Y. Ye and A. Borodin, Elimination graphs, ACM Trans. Algorithms 8(2) (2012) 1–23] for special cases) for approximating optimal weighted induced [math]-subgraphs and optimal [math]-colorings (for hereditary [math]’s) within multiplicative factors of (essentially) [math] and [math] respectively, where [math] denotes the inductive analogue (as defined in this work) of optimal size of an unweighted induced [math]-subgraph of the input and [math] is the minimum size of a forbidden induced subgraph of [math]. Our results generalize the previous result on efficiently approximating maximum independent sets and minimum colorings on graphs of bounded inductive independence number to optimal [math]-subgraphs and [math]-colorings for arbitrary hereditary classes [math]. As a corollary, it is also shown that any maximal [math]-subgraph approximates an optimal solution within a factor of [math] for unweighted graphs, where [math] is maximum size of any induced [math]-subgraph in any local neighborhood [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-17T08:00:00Z
      DOI: 10.1142/S1793830922500197
       
  • Resolving Roman domination in graphs

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      Authors: P. Roushini Leely Pushpam, B. Mahavir, M. Kamalam
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a graph and [math] be a Roman dominating function defined on [math]. Let [math] be some ordering of the vertices of [math]. For any [math], [math] is defined by [math]. If for all [math], [math], we have [math], that is [math], for some [math], then [math] is called a resolving Roman dominating function (RDF) on [math]. The weight of a resolving RDF [math] on [math] is [math]. The minimum weight of a resolving RDF on [math] is called the resolving Roman domination number of [math] and is denoted by [math]. A resolving RDF on [math] with weight [math] is called a [math]-function on [math]. In this paper, we find the resolving Roman domination number of certain well-known classes of graphs. We also categorize the class of graphs whose resolving Roman domination number equals their order.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-17T08:00:00Z
      DOI: 10.1142/S1793830922500288
       
  • A note on [math]-[math]-3 conjecture for Halin graphs

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      Authors: Xiaoli Jiang, Zhengke Miao, Xiaowei Yu
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The well-known 1-2-3 Conjecture asserts the edges of every connected graph with at least three vertices can be weighted with 1, 2 and 3 so that adjacent vertices receive distinct sums of weights. In this paper, we show this conjecture holds for Halin graph. Moreover, this bound is tight.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-17T08:00:00Z
      DOI: 10.1142/S179383092250032X
       
  • Second-stage spectrum of corona of two graphs

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      Authors: Renny P Varghese
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The derived graph of a simple graph [math], denoted by [math], is the graph having the same vertex set as [math], in which two vertices are adjacent if and only if their distance in [math] is two. The spectrum of derived graph of [math] is called the second-stage spectrum of [math]. In this paper, we will determine the second-stage spectrum (Laplace and signless Laplace spectrum) of the corona of two regular graphs with diameter less than or equal to two. The energy of the derived graph is called the second-stage energy of [math]. Here, we proved that the class of graphs [math] is integral if and only if [math] is a perfect square and the second-stage energy depends only on number of vertices. Moreover, we discuss some applications like the number of spanning trees, the Kirchhoff index and Laplacian-energy-like invariant of the newly constructed graph.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-17T08:00:00Z
      DOI: 10.1142/S1793830922500343
       
  • Total vertex-edge domination in graphs: Complexity and algorithms

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      Authors: Nitisha Singhwal, Palagiri Venkata Subba Reddy
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a simple, undirected and connected graph. A vertex [math] of a simple, undirected graph [math]-dominates all edges incident to at least one vertex in its closed neighborhood [math]. A set [math] of vertices is a vertex-edge dominating set of [math], if every edge of graph [math] is [math]-dominated by some vertex of [math]. A vertex-edge dominating set [math] of [math] is called a total vertex-edge dominating set if the induced subgraph [math] has no isolated vertices. The total vertex-edge domination number [math] is the minimum cardinality of a total vertex-edge dominating set of [math]. In this paper, we prove that the decision problem corresponding to [math] is NP-complete for chordal graphs, star convex bipartite graphs, comb convex bipartite graphs and planar graphs. The problem of determining [math] of a graph [math] is called the minimum total vertex-edge domination problem (MTVEDP). We prove that MTVEDP is linear time solvable for chain graphs and threshold graphs. We also show that MTVEDP can be approximated within approximation ratio of [math]. It is shown that the domination and total vertex-edge domination problems are not equivalent in computational complexity aspects. Finally, an integer linear programming formulation for MTVEDP is presented.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-15T08:00:00Z
      DOI: 10.1142/S1793830922500318
       
  • Constacyclic codes over the ring [math], [math] [math]

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      Authors: Shunhua Zhang
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be the ring [math], where [math] for any odd prime [math] and positive integer [math]. In this paper, we study constacyclic codes over the ring [math]. We define a Gray map by a matrix and decompose a constacyclic code over the ring [math] as the direct sum of constacyclic codes over [math], we also characterize self-dual constacyclic codes over the ring [math] and give necessary and sufficient conditions for constacyclic codes to be dual-containing. As an application, we give a method to construct quantum codes from dual-containing constacyclic codes over the ring [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-13T08:00:00Z
      DOI: 10.1142/S179383092250015X
       
  • Signed domination number of hypercubes

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      Authors: B. ShekinahHenry, Y. S. Irine Sheela
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The [math]-cube graph or hypercube [math] is the graph whose vertex set is the set of all [math]-dimensional Boolean vectors, two vertices being joined if and only if they differ in exactly one co-ordinate. The purpose of the paper is to investigate the signed domination number of this hypercube graphs. In this paper, signed domination number [math]-cube graph for odd [math] is found and the lower and upper bounds of hypercube for even [math] are found.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-13T08:00:00Z
      DOI: 10.1142/S179383092250029X
       
  • Graphs whose weak Roman domination number increases by the deletion of any
           edge

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      Authors: Rihab Hamid, Nour El Houda Bendahib, Mustapha Chellali, Nacéra Meddah
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a function on a graph [math]. A vertex [math] with [math] is said to be undefended with respect to [math] if it is not adjacent to a vertex [math] with [math]. A function [math] is called a weak Roman dominating function (WRDF) if each vertex [math] with [math] is adjacent to a vertex [math] with [math], such that the function [math] defined by [math], [math] and [math] for all [math], has no undefended vertex. The weight of a WRDF is the sum of its function values over all vertices, and the weak Roman domination number [math] is the minimum weight of a WRDF in [math]. In this paper, we consider the effects of edge deletion on the weak Roman domination number of a graph. We show that the deletion of an edge of [math] can increase the weak Roman domination number by at most 1. Then we give a necessary condition for [math]-ER-critical graphs, that is, graphs [math] whose weak Roman domination number increases by the deletion of any edge. Restricted to the class of trees, we provide a constructive characterization of all [math]-ER-critical trees.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-11T08:00:00Z
      DOI: 10.1142/S1793830922500069
       
  • Optimal rendezvous on a line by location-aware robots in the presence of
           spies

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      Authors: Huda Chuangpishit, Jurek Czyzowicz, Ryan Killick, Evangelos Kranakis, Danny Krizanc
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      A set of mobile robots is placed at arbitrary points of an infinite line. The robots are equipped with GPS devices and they may communicate their positions on the line to a central authority. The collection contains an unknown subset of “spies”, i.e., byzantine robots, which are indistinguishable from the non-faulty ones. The set of the non-faulty robots needs to rendezvous in the shortest possible time in order to perform some task, while the byzantine robots may try to delay their rendezvous for as long as possible. The problem facing a central authority is to determine trajectories for all robots so as to minimize the time until all the non-faulty robots have met. The trajectories must be determined without knowledge of which robots are faulty. Our goal is to minimize the competitive ratio between the time required to achieve the first rendezvous of the non-faulty robots and the time required for such a rendezvous to occur under the assumption that the faulty robots are known at the start. In this paper, we give rendezvous algorithms with bounded competitive ratio, where the central authority is informed only of the set of initial robot positions, without knowing which ones or how many of them are faulty. In general, regardless of the number of faults [math] it can be shown that there is an algorithm with bounded competitive ratio. Further, we are able to give a rendezvous algorithm with optimal competitive ratio provided that the number [math] of faults is strictly less than [math]. Note, however, that in general this algorithm does not give an estimate on the actual value of the competitive ratio. However, when an upper bound on the number of byzantine robots is known to the central authority, we can provide algorithms with constant competitive ratios and in some instances we are able to show that these algorithms are optimal. Moreover, in the cases where the number of faults is either [math] or [math] we are able to compute the competitive ratio of an optimal rendezvous algorithm, for a small number of robots.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-11T08:00:00Z
      DOI: 10.1142/S1793830922500306
       
  • On approximating MIS over [math]-VPG graphs

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      Authors: Abhiruk Lahiri, Joydeep Mukherjee, C. R. Subramanian
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      In this paper, we present an approximation algorithm for the maximum independent set (MIS) problem over the class of [math]-VPG graphs when the input is specified by a [math]-VPG representation. We obtain a [math]-approximation algorithm running in [math] time. This is an improvement over the previously best [math]-approximation algorithm [J. Fox and J. Pach, Computing the independence number of intersection graphs, in Proc. Twenty-Second Annual ACM-SIAM Symp. Discrete Algorithms (SODA 2011), 2011, pp. 1161–1165, doi:10.1137/1.9781611973082.87] (for some fixed [math]) designed for some subclasses of string graphs, on [math]-VPG graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-11T08:00:00Z
      DOI: 10.1142/S1793830922500355
       
  • On generalized adjacency Estrada index of graphs

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      Authors: Maryam Baghipur, Harishchandra S. Ramane
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The Estrada index is a graph-spectrum-based invariant having an important role in chemistry and physics. In this paper, we define the generalized adjacency Estrada index of a graph and obtain some lower and upper bounds for the generalized adjacency Estrada index in terms of various graph parameters associated with the structure of a graph. Further, we characterize the extremal graphs attaining these bounds. We also highlight the relationship between generalized adjacency Estrada index and generalized adjacency energy. Using these results, we obtain the improved bounds for the Estrada index based on the adjacency eigenvalues of a graph.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-10T08:00:00Z
      DOI: 10.1142/S1793830922500367
       
  • The connectivity and Hamiltonian properties of second-order circuit graphs
           of wheel cycle matroids

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      Authors: Zijian Deng, Bin Liu, Bofeng Huo, Bo Deng
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be the [math]th-order circuit graph of a simple connected matroid M. The first-order circuit graph is also called a circuit graph. There are lots of results about connectivity and Hamiltonian properties of circuit graph of matroid, while there are few related results on the second-order circuit graph of a matroid. This paper mainly focuses on the connectivity and Hamiltonian properties of the second-order circuit graphs of the cycle matroid of wheels. It determines the minimum degree and connectivity of these graphs, and proves that the second-order circuit graph of the cycle matroid of a wheel is uniformly Hamiltonian.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-06T07:00:00Z
      DOI: 10.1142/S1793830922500070
       
  • Sampling-based approximate skyline calculation on big data

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      Authors: Xingxing Xiao, Jianzhong Li
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Nowadays, big data is coming to the force in a lot of applications. Processing a skyline query on big data in more than linear time is by far too expensive and often even linear time may be too slow. It is obviously not possible to compute an exact solution to a skyline query in sublinear time, since an exact solution may itself have linear size. Fortunately, in many situations, a fast approximate solution is more useful than a slower exact solution. This paper proposes two sampling-based approximate algorithms for processing skyline queries. The first algorithm obtains a fixed size sample and computes the approximate skyline on it. The error of the algorithm is not only relatively small in most cases, but also is almost unaffected by the input size. The second algorithm returns an [math]-approximation for the exact skyline efficiently. The running time of the algorithm has nothing to do with the input size in practical, achieving the goal of sublinearity on big data. Experiments verify the error analysis of the first algorithm, and show that the second is much faster than the existing skyline algorithms.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-06T07:00:00Z
      DOI: 10.1142/S1793830922500240
       
  • A refinement of Dyck paths: A combinatorial approach

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      Authors: Rigoberto Flórez, José L. Ramírez, Fabio A. Velandia, Diego Villamizar
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Local maxima and minima of a Dyck path are called peaks and valleys, respectively. A Dyck path is called restricted[math]-Dyck if the difference between any two consecutive valleys is at least [math] (right-hand side minus left-hand side) or if it has at most one valley. In this paper, we use several techniques to enumerate some statistics over this new family of lattice paths. For instance, we use the symbolic method, the Chomsky–Schűtzenberger methodology, Zeilberger’s creative telescoping method, recurrence relations, and bijective relations. We count, for example, the number of paths of length [math], the number of peaks, the number of valleys, the number of peaks of a fixed height, and the area under the paths. We also give a bijection between the restricted [math]-Dyck paths and a family of binary words.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-11-06T07:00:00Z
      DOI: 10.1142/S1793830922500264
       
  • On the local irregularity vertex coloring of volcano, broom, parachute,
           double broom and complete multipartite graphs

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      Authors: Arika Indah Kristiana, Nafidatun Nikmah, Dafik, Ridho Alfarisi, M. Ali Hasan, Slamin
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a simple, finite, undirected, and connected graph with vertex set [math] and edge set [math]. A bijection [math] is label function [math] if [math] and for any two adjacent vertices [math] and [math], [math] where [math] and [math] is set ofvertices adjacent to [math]. [math] is called local irregularity vertex coloring. The minimum cardinality of local irregularity vertex coloring of [math] is called chromatic number local irregular denoted by [math]. In this paper, we verify the exact values of volcano, broom, parachute, double broom and complete multipartite graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-10-28T07:00:00Z
      DOI: 10.1142/S1793830922500227
       
  • Two-ended quasi-transitive graphs

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      Authors: Babak Miraftab, Tim Rühmann
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The well-known characterization of two-ended groups says that every two-ended group can be split over finite subgroups which means it is isomorphic to either by a free product with amalgamation [math] or an HNN-extension [math], where [math] is a finite group and [math] and [math]. In this paper, we show that there is a way in order to spilt two-ended quasi-transitive graphs without dominated ends and two-ended transitive graphs over finite subgraphs in the above sense. As an application of it, we characterize all groups acting with finitely many orbits almost freely on those graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-10-27T07:00:00Z
      DOI: 10.1142/S1793830922500239
       
  • Edge [math]-choosability of graphs

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      Authors: P. Soorya, K. A. Germina
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a simple, connected graph of order [math] and size [math] Then, [math] is said to be edge [math]-choosable, if there exists a collection of subsets of the edge set, [math] of cardinality [math] such that [math] whenever [math] and [math] are incident. This paper initiates a study on edge [math]-choosability of certain fundamental classes of graphs and determines the maximum value of [math] for which the given graph [math] is edge [math]-choosable. Also, in this paper, the relation between edge choice number and other graph theoretic parameters is discussed and we have given a conjecture on the relation between edge choice number and matching number of a graph.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-10-27T07:00:00Z
      DOI: 10.1142/S1793830922500252
       
  • Transitivity of trees

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      Authors: Libin Chacko Samuel, Mayamma Joseph
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      For a graph [math], a partition [math] of the vertex set [math] is a transitive partition if [math] dominates [math] whenever [math]. The transitivity [math] of a graph [math] is the maximum order of a transitive partition of [math]. For any positive integer [math], we characterize the smallest tree with transitivity [math] and obtain an algorithm to determine the transitivity of any tree of finite order.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-10-22T07:00:00Z
      DOI: 10.1142/S1793830922500203
       
  • Some properties of subgroup complementary addition Cayley graphs on
           abelian groups

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      Authors: Naveen Palanivel, Chithra A. Velu
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      In this paper, we introduce subgroup complementary addition Cayley graph [math] and compute its graph invariants. Also, we prove that [math] if and only if [math] for all [math] where [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-10-22T07:00:00Z
      DOI: 10.1142/S1793830922500215
       
  • Structure of super strongly perfect graphs

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      Authors: T. E. Soorya, Sunil Mathew
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Super strongly perfect graphs and their association with certain other classes of graphs are discussed in this paper. It is observed that every split graph is super strongly perfect. An existing result on super strongly perfect graphs is disproved providing a counter example. It is also established that if a graph [math] contains a cycle of odd length, then its line graph [math] is not always super strongly perfect. Complements of cycles of length six or above are proved to be non-super strongly perfect. If a graph is strongly perfect, then it is shown that they are super strongly perfect and hence all [math]-free graphs are super strongly perfect.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-10-12T07:00:00Z
      DOI: 10.1142/S1793830922500185
       
  • A remark on skew factorization and new [math]-linear codes

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      Authors: Padmapani Seneviratne
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Nine new [math] linear codes with lengths [math] and [math] that improve previously best known parameters are constructed. By modifying these codes, another 17 new codes are obtained. It is conjectured that the complete set of factors of [math] can be derived from the factors of [math] for even values of [math] in the skew polynomial ring [math]. It is further shown that the [math] code obtained is linearly complementary dual.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-09-29T07:00:00Z
      DOI: 10.1142/S1793830922500112
       
  • Total double Roman domination numbers in digraphs

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      Authors: J. Amjadi, F. Pourhosseini
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a finite and simple digraph with vertex set [math]. A double Roman dominating function (DRDF) on digraph [math] is a function [math] such that every vertex with label 0 has an in-neighbor with label 3 or two in-neighbors with label 2 and every vertex with label 1 have at least one in-neighbor with label at least 2. The weight of a DRDF [math] is the value [math]. A DRDF [math] on [math] with no isolated vertex is called a total double Roman dominating function if the subgraph of [math] induced by the set [math] has no isolated vertex. In this paper, we initiate the study of the total double Roman domination number in digraphs and show its relationship to other domination parameters. In particular, we present some bounds for the total double Roman domination number and we determine the total double Roman domination number of some classes of digraphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-09-28T07:00:00Z
      DOI: 10.1142/S1793830922500148
       
  • Movable resolving domination in graphs

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      Authors: Gerald B. Monsanto, Helen M. Rara
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a connected graph. Brigham et al., Resolving domination in graphs, Math. Bohem. 1 (2003) 25–36 defined a resolving dominating set as a set [math] of vertices of a connected graph [math] that is both resolving and dominating. A resolving dominating is a [math]-movable resolving dominating set of [math] if for every [math], either [math] is a resolving dominating set or there exists a vertex [math] such that [math] is a resolving dominating set of [math]. The minimum cardinality of a [math]-movable resolving dominating set of [math], denoted by [math] is the [math]-movable[math]-domination number of [math]. A [math]-movable resolving dominating set with cardinality [math] is called a [math]-set of [math]. In this paper, we characterize the [math]-movable resolving dominating sets in the join and lexicographic product of two graphs and determine the bounds or exact values of the [math]-movable resolving domination number of these graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-09-28T07:00:00Z
      DOI: 10.1142/S1793830922500161
       
  • On a conjecture of Laplacian energy of trees

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      Authors: Hilal A. Ganie, Bilal A. Rather, S. Pirzada
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a simple graph with [math] vertices, [math] edges having Laplacian eigenvalues [math]. The Laplacian energy LE[math] is defined as LE[math], where [math] is the average degree of [math]. Radenković and Gutman conjectured that among all trees of order [math], the path graph [math] has the smallest Laplacian energy. Let [math] be the family of trees of order [math] having diameter [math]. In this paper, we show that Laplacian energy of any tree [math] is greater than the Laplacian energy of [math], thereby proving the conjecture for all trees of diameter [math]. We also show the truth of conjecture for all trees with number of non-pendent vertices at most [math]. Further, we give some sufficient conditions for the conjecture to hold for a tree of order [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-09-06T07:00:00Z
      DOI: 10.1142/S1793830922500094
       
  • On some punctured codes of [math]-Simplex codes

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      Authors: J. Prabu, J. Mahalakshmi, C. Durairajan, S. Santhakumar
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      In this paper, we have constructed some new codes from [math]-Simplex code called unit [math]-Simplex code. In particular, we find the parameters of these codes and have proved that it is a [math] [math]-linear code, where [math] and [math] is a smallest prime divisor of [math]. When rank [math] and [math] is a prime power, we have given the weight distribution of unit [math]-Simplex code. For the rank [math] we obtain the partial weight distribution of unit [math]-Simplex code when [math] is a prime power. Further, we derive the weight distribution of unit [math]-Simplex code for the rank [math] [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-09-06T07:00:00Z
      DOI: 10.1142/S1793830922500124
       
  • Critical concepts of restrained domination in signed graphs

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      Authors: Anisha Jean Mathias, V. Sangeetha, Mukti Acharya
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      A signed graph [math] is a simple undirected graph in which each edge is either positive or negative. Restrained dominating set [math] in [math] is a restrained dominating set of the underlying graph [math] where the subgraph induced by the edges across [math] and within [math] is balanced. The minimum cardinality of a restrained dominating set of [math] is called the restrained domination number, denoted by [math]. In this paper, we initiate the study on various critical concepts to investigate the effect of edge removal or edge addition on restrained domination number in signed graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-08-31T07:00:00Z
      DOI: 10.1142/S1793830922500100
       
  • The projective [math]-annihilating-ideal hypergraphs

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      Authors: V. Ramanathan, C. Selvaraj
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      In this paper, we investigate the crosscap of 3-annihilating-ideal hypergraph [math] of a commutative ring [math] and the topological embedding of [math] to the nonorientable compact surfaces. Furthermore, we determine all Artinian commutative non-local rings [math] (up to isomorphism) such that [math] is a projective graph.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-08-28T07:00:00Z
      DOI: 10.1142/S1793830922500057
       
  • Restrained geodetic domination of edge subdivision graph

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      Authors: John Joy Mulloor, V. Sangeetha
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      For a connected graph [math], a set [math] subset of [math] is said to be a geodetic set if all vertices in [math] should lie in some [math] geodesic for some [math]. The minimum cardinality of the geodetic set is the geodetic number. In this paper, the authors discussed the geodetic number, geodetic domination number, and the restrained geodetic domination of the edge subdivision graph.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-08-21T07:00:00Z
      DOI: 10.1142/S1793830922500021
       
  • Hamiltonian trace graph of matrices

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      Authors: M. Sivagami, T. Tamizh Chelvam
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a commutative ring with identity, [math] be a positive integer and [math] be the set of all [math] matrices over [math] For a matrix [math] Tr[math] is the trace of [math] The trace graph of the matrix ring [math] denoted by [math] is the simple undirected graph with vertex set [math][math] and two distinct vertices [math] and [math] are adjacent if and only if Tr[math] The ideal-based trace graph of the matrix ring [math] with respect to an ideal [math] of [math] denoted by [math] is the simple undirected graph with vertex set [math] and two distinct vertices [math] and [math] are adjacent if and only if Tr[math] In this paper, we investigate some properties and structure of [math] Further, it is proved that both [math] and [math] are Hamiltonian.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-08-18T07:00:00Z
      DOI: 10.1142/S179383092250001X
       
  • Enumeration of [math]-hypergroups on sets with two elements

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      Authors: M. B. Safari, B. Davvaz
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      This paper is a continuation of ideas presented in [M. B. Safari, B. Davvaz and V. Leoreanu-Fotea, Enumeration of 3- and 4-hypergroups on sets with two elements, Eur. J. Combin. 44 (2015) 298–306]. We find the number and structure of non-isomorphism 5-hypergroups on sets with two elements. Moreover, we present a general template for some special cases of [math]-hypergroups by linking the last results on [math]-hypergroups.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-08-18T07:00:00Z
      DOI: 10.1142/S1793830922500033
       
  • Algorithmic aspects of outer independent Roman domination in graphs

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      Authors: Amit Sharma, Jakkepalli Pavan Kumar, P. Venkata Subba Reddy, S. Arumugam
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a connected graph. A function [math] is called a Roman dominating function if every vertex [math] with [math] is adjacent to a vertex [math] with [math]. If further the set [math] is an independent set, then [math] is called an outer independent Roman dominating function (OIRDF). Let [math] and [math]. Then [math] is called the outer independent Roman domination number of [math]. In this paper, we prove that the decision problem for [math] is NP-complete for chordal graphs. We also show that [math] is linear time solvable for threshold graphs and bounded tree width graphs. Moreover, we show that the domination and outer independent Roman domination problems are not equivalent in computational complexity aspects.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-08-18T07:00:00Z
      DOI: 10.1142/S1793830922500045
       
  • [math]-Gatherings on a star and uncertain [math]-gatherings on a line

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      Authors: Shareef Ahmed, Shin-ichi Nakano, Md. Saidur Rahman
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a set of [math] customers and [math] be a set of [math] facilities. An [math]-gather clustering of [math] is a partition of the customers in clusters such that each cluster contains at least [math] customers. The [math]-gather clustering problem asks to find an [math]-gather clustering which minimizes the maximum distance between a pair of customers in a cluster. An [math]-gathering of [math] to [math] is an assignment of each customer [math] to a facility [math] such that each facility has zero or at least [math] customers. The [math]-gathering problem asks to find an [math]-gathering that minimizes the maximum distance between a customer and his/her facility. In this work, we consider the [math]-gather clustering and [math]-gathering problems when the customers and the facilities are lying on a “star”. We show that the [math]-gather clustering problem and the [math]-gathering problem with customers and facilities on a star with [math] rays can be solved in [math] and [math] time, respectively. Furthermore, we prove the hardness of a variant of the [math]-gathering problem, called the min-max-sum [math]-gathering problem, even when the customers and the facilities are on a star. We also study the [math]-gathering problem when the customers and the facilities are on a line, and each customer location is uncertain. We show that the [math]-gathering problem can be solved in [math] and [math] time when the customers and the facilities are on a line, and the customer locations are given by piecewise uniform functions of at most [math] pieces and “well-separated” uniform distribution functions, respectively.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-08-05T07:00:00Z
      DOI: 10.1142/S1793830921501603
       
  • Algorithm to check the existence of [math] for a given [math] such that
           [math] is graphical

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      Authors: K. Arathi Bhat, G. Sudhakara, M. Vinay
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      A matrix with entries [math] is graphical if it is symmetric and all its diagonal entries are zero. Let [math], [math] and [math] be graphs defined on the same set of vertices. The graph [math] is said to be the matrix product of graphs [math] and [math], if [math], where [math] is the adjacency matrix of the graph [math]. In such a case, we say that [math] and [math] are companions of each other. The main purpose of this paper is to design an algorithm to check whether a given graph [math] has a companion. We derive conditions on [math] and [math] so that the generalized wheel graph, denoted by [math], has a companion and also show that the [math]th power of the path graph [math] has no companion. Finally, we indicate a possible application of the algorithm in a problem of coloring of edges of the complete graph [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-07-24T07:00:00Z
      DOI: 10.1142/S1793830921501597
       
  • A note on global dominator coloring of graphs

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      Authors: R. Rangarajan, David. A. Kalarkop
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Global dominator coloring of the graph [math] is the proper coloring of [math] such that every vertex of [math] dominates atleast one color class as well as anti-dominates atleast one color class. The minimum number of colors required for global dominator coloring of [math] is called global dominator chromatic number of [math] denoted by [math]. In this paper, we characterize trees [math] of order [math] [math] such that [math] and also establish a strict upper bound for [math] for a tree of even order [math] [math]. We construct some family of graphs [math] with [math] and prove some results on [math]-partitions of [math] when [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-07-21T07:00:00Z
      DOI: 10.1142/S1793830921501585
       
  • On [math]-irregularity strength of cycles and diamond graphs

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      Authors: Hayat Labane, Isma Bouchemakh, Andrea Semaničová-Feňovčíková
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      A simple graph [math] admits an [math]-covering if every edge in [math] belongs to at least one subgraph of [math] isomorphic to a given graph [math]. The graph [math] admits an [math]-irregular total[math]-labeling [math] if [math] admits an [math]-covering and for every two different subgraphs [math] and [math] isomorphic to [math], there is [math], where [math] is the associated [math]-weight. The total[math]-irregularity strength of [math] is [math]. In this paper, we give the exact values of [math], where [math]. For the versions edge and vertex [math]-irregularity strength [math] and [math], respectively, we determine the exact values of [math], [math] and [math], where [math] is the diamond graph.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-07-16T07:00:00Z
      DOI: 10.1142/S1793830921501573
       
  • Deep learning-based approximation of Goldbach partition function

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      Authors: Eunmi Kim
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Goldbach’s conjecture is one of the oldest and famous unproved problems in number theory. Using a deep learning model, we obtain an approximation of the Goldbach partition function, which counts the number of ways of representing an even number greater than 4 as a sum of two primes. We use residues of number modulo first 25 primes as features and archive a more accurate approximation, which reduces error rate from [math] to [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-07-10T07:00:00Z
      DOI: 10.1142/S1793830921501524
       
  • On generalized neighbor sum distinguishing index of planar graphs

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      Authors: Jieru Feng, Yue Wang, Jianliang Wu
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      For a proper [math]-edge coloring [math] of a graph [math], let [math] denote the sum of the colors taken on the edges incident to the vertex [math]. Given a positive integer [math], the [math]-neighbor sum distinguishing [math]-edge coloring of G is [math] such that for each edge [math], [math]. We denote the smallest integer [math] in such coloring of [math] by [math]. For [math], Wang et al. proved that [math]. In this paper, we show that if G is a planar graph without isolated edges, then [math], where [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-07-09T07:00:00Z
      DOI: 10.1142/S1793830921501470
       
  • Sharp lower bounds on the sum-connectivity index of trees

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      Authors: S. Alyar, R. Khoeilar
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The sum-connectivity index of a graph [math] is defined as the sum of weights [math] over all edges [math] of [math], where [math] and [math] are the degrees of the vertices [math] and [math] in [math], respectively. In this paper, some extremal problems on the sum-connectivity index of trees are studied. The extremal values on the sum-connectivity index of trees with given graphic parameters, such as pendant number, matching number, domination number and diameter, are determined. The corresponding extremal graphs are characterized, respectively.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-07-06T11:12:37Z
      DOI: 10.1142/S1793830921501536
       
  • Planar graphs without intersecting 5-cycles are signed-4-choosable

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      Authors: Seog-Jin Kim, Xiaowei Yu
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      A signed graph is a pair [math], where [math] is a graph and [math] is a signature of [math]. A set [math] of integers is symmetric if [math] implies that [math]. Given a list assignment [math] of [math], an [math]-coloring of a signed graph [math] is a coloring [math] of [math] such that [math] for each [math] and [math] for every edge [math]. The signed choice number [math] of a graph [math] is defined to be the minimum integer [math] such that for any [math]-list assignment [math] of [math] and for any signature [math] on [math], there is a proper [math]-coloring of [math]. List signed coloring is a generalization of list coloring. However, the difference between signed choice number and choice number can be arbitrarily large. Hu and Wu [Planar graphs without intersecting [math]-cycles are [math]-choosable, Discrete Math. 340 (2017) 1788–1792] showed that every planar graph without intersecting 5-cycles is 4-choosable. In this paper, we prove that [math] if [math] is a planar graph without intersecting 5-cycles, which extends the main result of [D. Hu and J. Wu, Planar graphs without intersecting [math]-cycles are [math]-choosable, Discrete Math. 340 (2017) 1788–1792].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-07-06T07:00:00Z
      DOI: 10.1142/S1793830921501512
       
  • On the double total dominator chromatic number of graphs

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      Authors: Fairouz Beggas, Hamamache Kheddouci, Walid Marweni
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      In this paper, we introduce and study a new coloring problem of graphs called the double total dominator coloring. A double total dominator coloring of a graph [math] with minimum degree at least 2 is a proper vertex coloring of [math] such that each vertex has to dominate at least two color classes. The minimum number of colors among all double total dominator coloring of [math] is called the double total dominator chromatic number, denoted by [math]. Therefore, we establish the close relationship between the double total dominator chromatic number [math] and the double total domination number [math]. We prove the NP-completeness of the problem. We also examine the effects on [math] when [math] is modified by some operations. Finally, we discuss the [math] number of square of trees by giving some bounds.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-07-06T07:00:00Z
      DOI: 10.1142/S1793830921501548
       
  • On the skew Laplacian spectral radius of a digraph

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      Authors: Bilal A. Chat, Hilal A. Ganie, Altaf A. Bhat, Mohd Y. Bhat, Mehraj A. Lone
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be an orientation of a simple graph [math] with [math] vertices and [math] edges. The skew Laplacian matrix [math] of the digraph [math] is defined as [math], where [math] is the imaginary unit, [math] is the diagonal matrix with oriented degrees [math] as diagonal entries and [math] is the skew matrix of the digraph [math]. The largest eigenvalue of the matrix [math] is called skew Laplacian spectral radius of the digraph [math]. In this paper, we study the skew Laplacian spectral radius of the digraph [math]. We obtain some sharp lower and upper bounds for the skew Laplacian spectral radius of a digraph [math], in terms of different structural parameters of the digraph and the underlying graph. We characterize the extremal digraphs attaining these bounds in some cases. Further, we end the paper with some problems for the future research in this direction.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-07-06T07:00:00Z
      DOI: 10.1142/S179383092150155X
       
  • A secure image cryptosystem via multiple chaotic maps

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      Authors: Mayada T. Wazi, Dalia S. Ali, Nadia M. G. Al-Saidi, Nawras A. Alawn
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      This work focused on introducing a new two-dimensional (2D) chaotic system. It is combined of some existing maps, the logistic, iterative chaotic map with infinite collapse, and Henon maps; we called it 2D-LCHM. The assessment of the actual performance of 2D-LCHM presents its sensitivity to a tiny change in the initial condition. Besides, its dynamics behavior is very complicated. It also has hyperchaotic properties and good ergodicity. The proposed system is occupied with designing a new image encryption system. Changing the image pixels’ locations is the primary step in the encryption process. The original image is splitting into four blocks to create four different keys based on 2D-LCHM; this reduces the computation time and increases the complexity. To obtain the encryption image, we have to repeat the partitioning process several times for each block. The encryption image’s efficiency is shown through some performance analysis such as; image histogram, the number of pixels changes rate (NPCR), the unified average changing intensity (UACI), pixels correlation, and entropy. The proposed system is compared with some efficient encryption algorithms in terms of chaocity attributes and image performance; the analysis result showed consistent improvement.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-07-05T07:00:00Z
      DOI: 10.1142/S179383092150141X
       
  • List injective coloring of planar graphs with disjoint [math]-cycles

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      Authors: Wenwen Li, Jiansheng Cai
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      An injective [math]-coloring of a graph [math] is called injective if any two vertices joined by a path of length two get different colors. A graph [math] is injectively [math]-choosable if for any color list [math] of admissible colors on [math] of size [math] it allows an injective coloring [math] such that [math] whenever [math]. Let [math], [math] denote the injective chromatic number and injective choosability number of [math], respectively. Let [math] be a plane with disjoint [math]-cycles and maximum degree [math]. We show that [math] if [math], then [math]; [math] if [math], then [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-06-26T07:00:00Z
      DOI: 10.1142/S1793830921501482
       
  • Notes on Latin square graphs and their domination numbers

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      Authors: Sara Pouyandeh, Maryam Golriz, Mohammad Reza Sorouhesh, Maryam Khademi
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      A Latin square graph [math] is a simple graph associated with a Latin square [math]. In this paper, we consider a Latin square graph [math] in which [math] and improve the upper bound of the domination number [math] by showing that [math]. Moreover, we study certain domination numbers like medium domination, accurate domination, independent transversal domination and vertex covering transversal domination for Latin square graphs of order [math] to give useful facts.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-06-21T07:00:00Z
      DOI: 10.1142/S1793830921501354
       
  • Exploiting the security of [math] through approximation of [math]

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      Authors: Saidu Isah Abubakar, Sadiq Shehu
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      This paper reports new techniques that exploit the security of the prime power moduli [math] using continued fraction method. Our study shows that the key equation [math] can be exploited using [math] as good approximation of [math]. This enables us to get [math] from the convergents of the continued fractions expansion of [math] where the bound of the private exponent is [math] which leads to the polynomial time factorization of the moduli [math]. We further report the polynomial time attacks that can break the security of the generalized prime power moduli [math] using generalized system of equation of the form [math] and [math] by applying simultaneous Diophantine approximations and LLL algorithm techniques where [math] and [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-06-21T07:00:00Z
      DOI: 10.1142/S1793830921501445
       
  • The minus total [math]-domination numbers in graphs

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      Authors: Jonecis Dayap, Nasrin Dehgardi, Leila Asgharsharghi, Seyed Mahmoud Sheikholeslami
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      For any integer [math], a minus total [math]-dominating function is a function [math] satisfying [math] for every [math], where [math]. The minimum of the values of [math], taken over all minus total [math]-dominating functions [math], is called the minus total [math]-domination number and is denoted by [math]. In this paper, we initiate the study of minus total [math]-domination in graphs, and we present different sharp bounds on [math]. In addition, we determine the minus total [math]-domination number of some classes of graphs. Some of our results are extensions of known properties of the minus total domination number [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-06-21T07:00:00Z
      DOI: 10.1142/S1793830921501500
       
  • Square element graph of square-subtract rings

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      Authors: Bijon Biswas, S. Kar, M. K. Sen
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      If [math] is a ring then the square element graph [math] is the simple undirected graph whose vertex set consists of all non-zero elements of [math] and two distinct vertices [math] are adjacent if and only if [math] for some [math]. In this paper, we provide some necessary and sufficient conditions for the connectedness of [math], where [math] is a ring with identity. We mainly characterize some special class of ring [math] which we call square-subtract ring for which the graph [math] is connected.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-06-18T07:00:00Z
      DOI: 10.1142/S1793830921501421
       
  • Gravitational community detection by predicting diameter

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      Authors: Himansu Sekhar Pattanayak, Harsh K. Verma, Amrit Lal Sangal
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Community detection is a pivotal part of network analysis and is classified as an NP-hard problem. In this paper, a novel community detection algorithm is proposed, which probabilistically predicts communities’ diameter using the local information of random seed nodes. The gravitation method is then applied to discover communities surrounding the seed nodes. The individual communities are combined to get the community structure of the whole network. The proposed algorithm, named as Local Gravitational community detection algorithm (LGCDA), can also work with overlapping communities. LGCDA algorithm is evaluated based on quality metrics and ground-truth data by comparing it with some of the widely used community detection algorithms using synthetic and real-world networks.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-06-18T07:00:00Z
      DOI: 10.1142/S1793830921501457
       
  • Triangulability of convex graphs and convex skewness

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      Authors: Niran Abbas Ali, Gek L. Chia, Hazim Michman Trao, Adem Kilicman
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Suppose [math] is a subgraph of a convex complete graph [math] and [math] contains no boundary edge of [math] and [math]. We determine necessary and sufficient conditions on [math] such that [math] admits a triangulation. For [math], we investigate the possibility of placing [math] in [math] such that [math] admits a triangulation for certain families of graphs [math]. These results are then applied to determine the convex skewness of the convex graphs of the form [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-06-18T07:00:00Z
      DOI: 10.1142/S1793830921501469
       
  • Bounds and extremal graphs for Harary energy

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      Authors: A. Alhevaz, M. Baghipur, H. A. Ganie, K. C. Das
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a connected graph of order [math] and let [math] be the reciprocal distance matrix (also called Harary matrix) of the graph [math]. Let [math] be the eigenvalues of the reciprocal distance matrix [math] of the connected graph [math] called the reciprocal distance eigenvalues of [math]. The Harary energy [math] of a connected graph [math] is defined as sum of the absolute values of the reciprocal distance eigenvalues of [math], that is, [math] In this paper, we establish some new lower and upper bounds for [math] in terms of different graph parameters associated with the structure of the graph [math]. We characterize the extremal graphs attaining these bounds. We also obtain a relation between the Harary energy and the sum of [math] largest adjacency eigenvalues of a connected graph.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-06-18T07:00:00Z
      DOI: 10.1142/S1793830921501494
       
  • On skew cyclic codes over a mixed alphabet and their applications to DNA
           codes

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      Authors: Abdullah Dertli, Yasemin Cengellenmis, Nuh Aydin
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      In this paper, we introduce skew cyclic codes over the mixed alphabet [math], where [math] is the finite field with 4 elements and [math]. Our results include a description of the generator polynomials of such codes and a necessary and sufficient condition for an [math]-skew cyclic code to be reversible complement.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-06-11T07:00:00Z
      DOI: 10.1142/S1793830921501433
       
  • On the square coloring of comparability graphs

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      Authors: Mehmet Akif Yetim
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      We find sufficient conditions for the square of a comparability graph [math] of a poset [math] to be [math]-colorable when [math] lacks [math] for some [math]. Furthermore, we show that the problem of coloring the square of the comparability graph of a poset of height at least four can be reduced to the case of height three, where the height of a poset is the size of a maximum chain.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-06-07T07:00:00Z
      DOI: 10.1142/S1793830921501391
       
  • General sum-connectivity index of unicyclic graphs with given diameter and
           girth

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      Authors: Tomáš Vetrík
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Topological indices of graphs have been studied due to their extensive applications in chemistry. We obtain lower bounds on the general sum-connectivity index [math] for unicyclic graphs [math] of given girth and diameter, and for unicyclic graphs of given diameter, where [math]. We present the extremal graphs for all the bounds. Our results generalize previously known results on the harmonic index for unicyclic graphs of given diameter.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-06-07T07:00:00Z
      DOI: 10.1142/S1793830921501408
       
  • Sharp lower bounds on the sum-connectivity index of quasi-tree graphs

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      Authors: Amir Taghi Karimi
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The sum-connectivity index of a graph [math] is defined as the sum of weights [math] over all edges [math] of [math], where [math] and [math] are the degrees of the vertices [math] and [math] in [math], respectively. A graph [math] is called quasi-tree, if there exists [math] such that [math] is a tree. In the paper, we give a sharp lower bound on the sum-connectivity index of quasi-tree graphs.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-05-31T07:00:00Z
      DOI: 10.1142/S1793830921501366
       
  • Super domination in trees

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      Authors: B. Senthilkumar, Y. B. Venkatakrishnan, H. Naresh Kumar
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a simple graph. A set [math] is called a super dominating set if for every vertex [math], there exist [math] such that [math]. The minimum cardinality of a super dominating set of [math], denoted by [math], is called the super domination number of graph [math]. Characterization of trees with [math] is presented.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-05-28T07:00:00Z
      DOI: 10.1142/S1793830921501378
       
  • More on the unimodality of domination polynomial of a graph

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      Authors: Gee-Choon Lau, Saeid Alikhani
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      Let [math] be a graph of order [math]. A subset [math] of [math] is a dominating set of [math] if every vertex in [math] is adjacent to at least one vertex of [math]. The domination polynomial of [math] is the polynomial [math], where [math] is the number of dominating sets of [math] of size [math], and [math] is the size of a smallest dominating set of [math], called the domination number of [math]. Motivated by a conjecture in [S. Alikhani and Y. H. Peng, Introduction to domination polynomial of a graph, ARS Combin. 114 (2014) 257–266] which states that the domination polynomial of any graph is unimodal, we obtain sufficient conditions for this conjecture to hold. Also we study the unimodality of graph [math] with [math], where [math] is an integer.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-05-28T07:00:00Z
      DOI: 10.1142/S179383092150138X
       
  • Graphs with constant adjacency dimension

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      Authors: Mohsen Jannesari
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      For a set [math] of vertices and a vertex [math] in a graph [math], the [math]-vector [math] is the adjacency representation of [math] with respect to [math], where [math] and [math] is the minimum of [math] and the distance between the vertices [math] and [math]. The set [math] is an adjacency resolving set for [math] if distinct vertices of [math] have distinct adjacency representations with respect to [math]. The minimum cardinality of an adjacency resolving set for [math] is its adjacency dimension. It is clear that the adjacency dimension of an [math]-vertex graph [math] is between [math] and [math]. The graphs with adjacency dimension [math] and [math] are known. All graphs with adjacency dimension [math], and all [math]-vertex graphs with adjacency dimension [math] are studied in this paper. In terms of the diameter and order of [math], a sharp upper bound is found for adjacency dimension of [math]. Also, a sharp lower bound for adjacency dimension of [math] is obtained in terms of order of [math]. Using these two bounds, all graphs with adjacency dimension 2, and all [math]-vertex graphs with adjacency dimension [math] are characterized.
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-05-19T07:00:00Z
      DOI: 10.1142/S1793830921501342
       
  • On neighborhood graphs: Domination, coloring and other properties

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      Authors: Angsuman Das
      Abstract: Discrete Mathematics, Algorithms and Applications, Ahead of Print.
      The neighborhood graph [math] of a graph [math] has the same vertex set as [math] and two vertices are adjacent in [math] if and only if they have a common neighbor in [math]. We study the domination number, independence number and chromatic number of [math] in terms of those of [math]. Moreover we investigate various structural similarities between [math] and [math].
      Citation: Discrete Mathematics, Algorithms and Applications
      PubDate: 2021-05-17T07:00:00Z
      DOI: 10.1142/S1793830921501330
       
 
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