Subjects -> ENGINEERING (Total: 2688 journals)
    - CHEMICAL ENGINEERING (229 journals)
    - CIVIL ENGINEERING (237 journals)
    - ELECTRICAL ENGINEERING (176 journals)
    - ENGINEERING (1325 journals)
    - ENGINEERING MECHANICS AND MATERIALS (452 journals)
    - HYDRAULIC ENGINEERING (56 journals)
    - INDUSTRIAL ENGINEERING (98 journals)
    - MECHANICAL ENGINEERING (115 journals)

ENGINEERING (1325 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted by number of followers
Composite Structures     Hybrid Journal   (Followers: 244)
IEEE Spectrum     Full-text available via subscription   (Followers: 219)
Composites Part B : Engineering     Hybrid Journal   (Followers: 218)
ACS Nano     Hybrid Journal   (Followers: 181)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 173)
Composites Science and Technology     Hybrid Journal   (Followers: 150)
IEEE Geoscience and Remote Sensing Letters     Hybrid Journal   (Followers: 148)
IEEE Instrumentation & Measurement Magazine     Hybrid Journal   (Followers: 148)
IEEE Communications Magazine     Full-text available via subscription   (Followers: 139)
IEEE Engineering Management Review     Full-text available via subscription   (Followers: 117)
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 112)
IEEE Transactions on Control Systems Technology     Hybrid Journal   (Followers: 111)
IEEE Transactions on Instrumentation and Measurement     Hybrid Journal   (Followers: 106)
IEEE Transactions on Signal Processing     Hybrid Journal   (Followers: 92)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 88)
IEEE Industry Applications Magazine     Full-text available via subscription   (Followers: 82)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 78)
IEEE Transactions on Engineering Management     Hybrid Journal   (Followers: 74)
Engineering Failure Analysis     Hybrid Journal   (Followers: 68)
IEEE Microwave Magazine     Full-text available via subscription   (Followers: 63)
IEEE Signal Processing Letters     Hybrid Journal   (Followers: 60)
IEEE Transactions on Reliability     Hybrid Journal   (Followers: 53)
Experimental Techniques     Hybrid Journal   (Followers: 51)
IET Radar, Sonar & Navigation     Open Access   (Followers: 50)
IEEE Transactions on Microwave Theory and Techniques     Hybrid Journal   (Followers: 49)
Control Engineering Practice     Hybrid Journal   (Followers: 46)
IEEE Journal of Selected Topics in Signal Processing     Hybrid Journal   (Followers: 43)
Biotechnology Progress     Hybrid Journal   (Followers: 42)
IEEE Potentials     Full-text available via subscription   (Followers: 42)
IEEE Journal on Selected Areas in Communications     Hybrid Journal   (Followers: 39)
Heat Transfer Engineering     Hybrid Journal   (Followers: 36)
IET Microwaves, Antennas & Propagation     Open Access   (Followers: 35)
International Journal for Numerical Methods in Engineering     Hybrid Journal   (Followers: 35)
IEEE Microwave and Wireless Components Letters     Hybrid Journal   (Followers: 35)
Digital Signal Processing     Hybrid Journal   (Followers: 34)
IEEE Transactions on Knowledge and Data Engineering     Hybrid Journal   (Followers: 31)
AIChE Journal     Hybrid Journal   (Followers: 31)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 31)
Computers & Geosciences     Hybrid Journal   (Followers: 30)
Flow, Turbulence and Combustion     Hybrid Journal   (Followers: 30)
Coastal Management     Hybrid Journal   (Followers: 29)
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 28)
GPS Solutions     Hybrid Journal   (Followers: 28)
Fluid Dynamics     Hybrid Journal   (Followers: 27)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 27)
Géotechnique     Hybrid Journal   (Followers: 27)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 27)
IEEE Transactions on Power Delivery     Hybrid Journal   (Followers: 26)
Applied Energy     Partially Free   (Followers: 26)
Advances in Engineering Software     Hybrid Journal   (Followers: 26)
IEEE Journal of Solid-State Circuits     Full-text available via subscription   (Followers: 24)
Corrosion Science     Hybrid Journal   (Followers: 23)
Engineering & Technology     Hybrid Journal   (Followers: 22)
IET Image Processing     Open Access   (Followers: 22)
Intermetallics     Hybrid Journal   (Followers: 21)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 21)
IEEE Transactions on Electronics Packaging Manufacturing     Hybrid Journal   (Followers: 21)
IET Signal Processing     Open Access   (Followers: 21)
IEEE Transactions on Circuits and Systems II: Express Briefs     Hybrid Journal   (Followers: 20)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 20)
Implementation Science     Open Access   (Followers: 20)
International Communications in Heat and Mass Transfer     Hybrid Journal   (Followers: 19)
Engineering Optimization     Hybrid Journal   (Followers: 19)
International Journal for Numerical Methods in Fluids     Hybrid Journal   (Followers: 19)
Electrophoresis     Hybrid Journal   (Followers: 18)
IET Circuits, Devices & Systems     Open Access   (Followers: 18)
IEEE/ACM Transactions on Computational Biology and Bioinformatics     Hybrid Journal   (Followers: 18)
IEEE Transactions on Intelligent Transportation Systems     Hybrid Journal   (Followers: 17)
Experiments in Fluids     Hybrid Journal   (Followers: 17)
Computational Geosciences     Hybrid Journal   (Followers: 17)
International Journal of Adhesion and Adhesives     Hybrid Journal   (Followers: 17)
Integration     Hybrid Journal   (Followers: 16)
IEEE Transactions on Energy Conversion     Hybrid Journal   (Followers: 16)
Engineering Geology     Hybrid Journal   (Followers: 16)
European Journal of Mass Spectrometry     Hybrid Journal   (Followers: 16)
Energy Conversion and Management     Hybrid Journal   (Followers: 15)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 15)
Coastal Engineering     Hybrid Journal   (Followers: 15)
IEEE Transactions on Magnetics     Hybrid Journal   (Followers: 14)
IEEE Journal of Biomedical and Health Informatics     Hybrid Journal   (Followers: 14)
IEEE Transactions on Automation Science and Engineering     Full-text available via subscription   (Followers: 13)
IEEE Transactions on Evolutionary Computation     Hybrid Journal   (Followers: 13)
Electromagnetics     Hybrid Journal   (Followers: 13)
Computers and Geotechnics     Hybrid Journal   (Followers: 12)
IEEE Transactions on Semiconductor Manufacturing     Hybrid Journal   (Followers: 12)
IET Renewable Power Generation     Open Access   (Followers: 12)
Human Factors in Ergonomics & Manufacturing     Hybrid Journal   (Followers: 12)
IEEE Transactions on Professional Communication     Hybrid Journal   (Followers: 11)
Biomedical Engineering     Hybrid Journal   (Followers: 11)
IEEE Transactions on Education     Hybrid Journal   (Followers: 11)
CIRP Annals - Manufacturing Technology     Hybrid Journal   (Followers: 11)
IEEE Journal of Oceanic Engineering     Hybrid Journal   (Followers: 11)
Heat Transfer - Asian Research     Hybrid Journal   (Followers: 10)
International Journal of Antennas and Propagation     Open Access   (Followers: 10)
Proceedings of the Institution of Civil Engineers - Geotechnical Engineering     Hybrid Journal   (Followers: 10)
IEEE Transactions on Nuclear Science     Hybrid Journal   (Followers: 10)
IEEE Transactions on Plasma Science     Hybrid Journal   (Followers: 10)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 9)
Fuel Cells Bulletin     Full-text available via subscription   (Followers: 9)
Computational Optimization and Applications     Hybrid Journal   (Followers: 9)
Annals of Science     Hybrid Journal   (Followers: 9)
European Journal of Engineering Education     Hybrid Journal   (Followers: 9)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 9)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
IEEE Technology and Society Magazine     Full-text available via subscription   (Followers: 8)
Fuel Cells     Hybrid Journal   (Followers: 8)
Adaptive Behavior     Hybrid Journal   (Followers: 8)
Proceedings of the Institution of Civil Engineers - Bridge Engineering     Hybrid Journal   (Followers: 8)
Energy Engineering     Full-text available via subscription   (Followers: 8)
IEEE Transactions on Advanced Packaging     Full-text available via subscription   (Followers: 8)
Clay Minerals     Hybrid Journal   (Followers: 8)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 8)
Applied Catalysis A: General     Hybrid Journal   (Followers: 7)
International Journal of Applied Ceramic Technology     Hybrid Journal   (Followers: 7)
Basin Research     Hybrid Journal   (Followers: 7)
Discrete Optimization     Full-text available via subscription   (Followers: 7)
Designs, Codes and Cryptography     Hybrid Journal   (Followers: 7)
IEEE Journal of Selected Topics in Quantum Electronics     Hybrid Journal   (Followers: 7)
Environmental and Ecological Statistics     Hybrid Journal   (Followers: 7)
Biomicrofluidics     Open Access   (Followers: 7)
Geothermics     Hybrid Journal   (Followers: 7)
Fuel and Energy Abstracts     Full-text available via subscription   (Followers: 7)
IEEE Vehicular Technology Magazine     Full-text available via subscription   (Followers: 7)
Catalysis Communications     Hybrid Journal   (Followers: 7)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 7)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Fusion Engineering and Design     Hybrid Journal   (Followers: 6)
Applied Clay Science     Hybrid Journal   (Followers: 6)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Formal Methods in System Design     Hybrid Journal   (Followers: 6)
Acta Geotechnica     Hybrid Journal   (Followers: 6)
Advances in OptoElectronics     Open Access   (Followers: 6)
International Journal of Adaptive Control and Signal Processing     Hybrid Journal   (Followers: 5)
IEEE Transactions on Vehicular Technology     Hybrid Journal   (Followers: 5)
IET Science, Measurement & Technology     Open Access   (Followers: 5)
IEEE Transactions on Applied Superconductivity     Hybrid Journal   (Followers: 5)
International Journal of Architectural Computing     Full-text available via subscription   (Followers: 5)
Finite Fields and Their Applications     Full-text available via subscription   (Followers: 5)
Focus on Powder Coatings     Full-text available via subscription   (Followers: 5)
Engineering With Computers     Hybrid Journal   (Followers: 5)
Proceedings of the Institution of Civil Engineers - Engineering Sustainability     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 5)
Active and Passive Electronic Components     Open Access   (Followers: 5)
Proceedings of the Institution of Civil Engineers - Ground Improvement     Hybrid Journal   (Followers: 4)
Frontiers in Energy     Hybrid Journal   (Followers: 4)
Adsorption     Hybrid Journal   (Followers: 4)
Catalysis Today     Hybrid Journal   (Followers: 4)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 4)
Current Applied Physics     Full-text available via subscription   (Followers: 4)
Fluid Phase Equilibria     Hybrid Journal   (Followers: 4)
Graphs and Combinatorics     Hybrid Journal   (Followers: 4)
Filtration & Separation     Full-text available via subscription   (Followers: 4)
Annals of Pure and Applied Logic     Open Access   (Followers: 4)
Grass and Forage Science     Hybrid Journal   (Followers: 4)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 4)
Informatik-Spektrum     Hybrid Journal   (Followers: 3)
Engineering Computations     Hybrid Journal   (Followers: 3)
European Journal of Combinatorics     Full-text available via subscription   (Followers: 3)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 3)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 3)
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Focus on Pigments     Full-text available via subscription   (Followers: 3)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Frontiers of Environmental Science & Engineering     Hybrid Journal   (Followers: 3)
Fuzzy Sets and Systems     Hybrid Journal   (Followers: 3)
Catalysis Letters     Hybrid Journal   (Followers: 3)
IET Generation, Transmission & Distribution     Open Access   (Followers: 2)
Historical Records of Australian Science     Hybrid Journal   (Followers: 2)
IET Optoelectronics     Open Access   (Followers: 2)
Assembly Automation     Hybrid Journal   (Followers: 2)
International Journal of Abrasive Technology     Hybrid Journal   (Followers: 2)
Aerobiologia     Hybrid Journal   (Followers: 2)
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 2)
Comptes Rendus : Mécanique     Open Access   (Followers: 2)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
IEEE Latin America Transactions     Full-text available via subscription   (Followers: 2)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
ESAIM: Control Optimisation and Calculus of Variations     Open Access   (Followers: 2)
Focus on Surfactants     Full-text available via subscription   (Followers: 2)
Engineering Analysis with Boundary Elements     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 1)
Foundations of Science     Hybrid Journal   (Followers: 1)
Forschung     Hybrid Journal   (Followers: 1)
European Journal of Lipid Science and Technology     Hybrid Journal   (Followers: 1)
Antarctic Science     Hybrid Journal   (Followers: 1)
Épités - Épitészettudomány     Full-text available via subscription   (Followers: 1)
Dyes and Pigments     Hybrid Journal   (Followers: 1)
Bautechnik     Hybrid Journal   (Followers: 1)
Biointerphases     Open Access   (Followers: 1)
Designed Monomers and Polymers     Open Access   (Followers: 1)
Color Research & Application     Hybrid Journal   (Followers: 1)
Abstract and Applied Analysis     Open Access   (Followers: 1)
Focus on Catalysts     Full-text available via subscription  
ESAIM: Proceedings     Open Access  
Environmetrics     Hybrid Journal  
COMBINATORICA     Hybrid Journal  
Chinese Science Bulletin     Open Access  
Calphad     Hybrid Journal  
Boundary Value Problems     Open Access  

        1 2 3 4 5 6 7 | Last

Similar Journals
Journal Cover
Graphs and Combinatorics
Journal Prestige (SJR): 0.728
Citation Impact (citeScore): 1
Number of Followers: 4  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1435-5914 - ISSN (Online) 0911-0119
Published by Springer-Verlag Homepage  [2469 journals]
  • Neighborhood Complexes, Homotopy Test Graphs and an Application to
           Coloring of Product Graphs

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      Abstract: The neighborhood complex \(\mathcal {N}(G)\) of a graph G was introduced by L. Lovász in his proof of Kneser conjecture. He proved that for any graph G, 2 $$\begin{aligned} \chi (G) \ge conn(\mathcal {N}(G))+3. \end{aligned}$$ In this article we show that for a class of exponential graphs the bound given in (2) is tight. Further, we show that the neighborhood complexes of these exponential graphs are spheres up to homotopy. We were also able to find a class of exponential graphs, which are homotopy test graphs. In 1966, Hedetniemi conjectured that the chromatic number of the categori-cal product of two graphs is the minimum of the chromatic number of the factors. In 2019, Shitov [26] gave a counterexample to this conjecture. Let M(G) denotes the Mycielskian of a graph G. We show that, for any graph G containing \(M(M(K_n))\) as a subgraph and for any graph H, if \(\chi (G \times H) = n+1\) , then \(\min \{\chi (G), \chi (H)\} = n+1\) . Therefore, we enrich the family of graphs satisfying the Hedetniemi’s conjecture.
      PubDate: 2022-05-13
       
  • Fashion Game on Planar Graphs

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      Abstract: This paper studies an optimization problem of the fashion game on graphs on surfaces, especially on planar graphs. There are rebel players in a graph G. All players choose their actions from an identical set of the two symmetric actions, say \(\{0,1\}\) . An action profile of G is a mapping \(\pi :V(G)\rightarrow \{0,1\}\) . A rebel likes people having the different action with her and dislikes people having the same action. The utility \(u(v,\pi )\) of a player v under the action profile \(\pi\) is the number of neighbors she likes minus the number of neighbors she dislikes. Let \(\phi :V(G)\rightarrow {\mathbb {Z}}\) be a function. The \(\phi\) -satisfiability problem is to determine whether a graph has an action profile under which each player v has a utility at least \(\phi (v)\) . Let t be an integer. The t-satisfiability problem is the specialized \(\phi\) -satisfiability problem when \(\phi (v)=t\) , for each \(v\in V(G)\) . The utility of G, denoted by u(G), is defined to be the maximum t such that G is t-satisfiable. Let \(\eta : V(G)\rightarrow {\mathbb {N}}\) be a function. A mapping \(c:\ V(G)\rightarrow \{0,1\}\) is called an \(\eta\) -defective 2-coloring of G if every \(v\in V(G)\) has at most \(\eta (v)\) neighbors that have the same color with it. For graphs embeddable in surfaces, upper bounds of their utilities are given. The graphs embeddable in the torus or the Klein bottle whose utilities reach their upper bounds are determined. The t-satisfiability problem for graphs embeddable in the plane, the projective plane, the torus, or the Klein bottle is NP-complete if \(t\in \{1,2,3\}\) , and is polynomial time solvable otherwise. We design a dynamic programming algorithm that solves the \(\phi\) -satisfiability problem for outerplanar graphs in \(O( V(G) ^3)\) time. This algorithm can also solve the \(\eta\) -defective 2-coloring problem for outerplanar graphs.
      PubDate: 2022-05-12
       
  • Equivariant Euler Characteristics of Symplectic Buildings

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      Abstract: We compute the equivariant Euler characteristics of the buildings for the symplectic groups over finite fields.
      PubDate: 2022-05-11
       
  • On the Unimodality of Domination Polynomials

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      Abstract: A polynomial is said to be unimodal if its coefficients are non-decreasing and then non-increasing. The domination polynomial of a graph G is the generating function of the number of dominating sets of each cardinality in G, and its coefficients have been conjectured to be unimodal. In this paper we will show the domination polynomial of paths, cycles and complete multipartite graphs are unimodal, and that the domination polynomial of almost every graph is unimodal with mode \( \lceil \frac{n}{2}\rceil \) .
      PubDate: 2022-05-09
       
  • Weakly Distance-Regular Digraphs of One Type of Arcs

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      Abstract: In this paper, we classify all commutative weakly distance-regular digraphs of girth g and one type of arcs under the assumption that \(p_{(1,g-1),(1,g-1)}^{(2,g-2)}\ge k_{1,g-1}-2\) . In consequence, Yang et al. (J Comb Theory Ser A 160:288–315, 2018, Theorem 1.1) is partially generalized by our result.
      PubDate: 2022-05-04
       
  • On a List Variant of the Multiplicative 1-2-3 Conjecture

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      Abstract: The 1-2-3 Conjecture asks whether almost all graphs can be (edge-)labelled with 1, 2, 3 so that no two adjacent vertices are incident to the same sum of labels. In the last decades, several aspects of this problem have been studied in literature, including more general versions and slight variations. Notable such variations include the List 1-2-3 Conjecture variant, in which edges must be assigned labels from dedicated lists of three labels, and the Multiplicative 1-2-3 Conjecture variant, in which labels 1, 2, 3 must be assigned to the edges so that adjacent vertices are incident to different products of labels. Several results obtained towards these two variants led to observe some behaviours that are distant from those of the original conjecture. In this work, we consider the list version of the Multiplicative 1-2-3 Conjecture, proposing the first study dedicated to this very problem. In particular, given any graph G, we wonder about the minimum k such that G can be labelled as desired when its edges must be assigned labels from dedicated lists of size k. Exploiting a relationship between our problem and the List 1-2-3 Conjecture, we provide upper bounds on k when G belongs to particular classes of graphs. We further improve some of these bounds through dedicated arguments.
      PubDate: 2022-05-04
       
  • Embedding Grid Graphs on Surfaces

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      Abstract: Abstract In this paper, we analyze embeddings of grid graphs on orientable surfaces. We determine the genus of two infinite classes of 3-dimensional grid graphs that do not admit quadrilateral embeddings and effective upper bounds for the genus of any 3-dimensional grid graph, both in terms of a grid graph’s combinatorics. As an application, we provide a complete classification of planar and toroidal grid graphs. Our work requires a variety of combinatorial and graph theoretic arguments to determine effective lower bounds on the genus of a grid graph, along with explicitly constructing embeddings of grid graphs on surfaces to determine effective upper bounds on their genera.
      PubDate: 2022-04-16
       
  • The Dichromatic Polynomial of a Digraph

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      Abstract: Abstract Let \(\lambda \) be a positive integer. An acyclic \(\lambda \) -coloring of a digraph D is a partition of the vertices of D into \(\lambda \) color clases such that the color classes induce acyclic subdigraphs in D. The minimum integer \(\lambda \) for which there exists an acyclic \(\lambda \) -coloring of D is the dichromatic number dc(D) of D. Let \(P(D;\lambda )\) be the dichromatic polynomial of D, which is the number of acyclic \(\lambda \) -colorings of D. In this paper, a recursive formula for \(P(D;\lambda )\) is given. The coefficients of the polynomial \(P(D;\lambda )\) are studied. The dichromatic polynomial of a digraph D is related to the structure of its underlying graph UG(D). Also, we study dichromatic equivalently and dichromatically unique digraphs.
      PubDate: 2022-04-16
       
  • Greedy Routing in Circulant Networks

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      Abstract: Abstract We address the problem of constructing large circulant networks with given degree and diameter, and efficient routing schemes. First we discuss the theoretical upper bounds and their asymptotics. Then we apply concepts and tools from the change-making problem to efficient routing in circulant graphs. With these tools we investigate some of the families of circulant graphs that have been proposed in the literature, and we construct tables of large circulant graphs and digraphs with efficient routing properties.
      PubDate: 2022-04-16
       
  • The Turán Numbers of Special Forests

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      Abstract: Abstract A graph is called H-free if it does not contain H as a subgraph. The Turán number of H, denoted by ex(n, H), is the maximum number of edges in any H-free graph on n vertices. For sufficiently large n, Lidický et al. (Electron J Combin 20:62, 2013) determined ex(n, F), where F denotes a class of forest with components each of order 4, and they characterized all the extremal graphs. Moreover, Lan et al. (Appl Math Comput 348: 270–274, 2019) proved that the extremal graph is unique when n is large enough. Motivated by their results, we consider a class of forests F with each component a path or star of order 6, we determine ex(n, F) for sufficiently large n and we also characterize all the extremal graphs. Furthermore, we prove that the extremal graph is unique when n is large enough. Let \(kP_n\) denote the disjoint union of k copies of the path \(P_n\) on n vertices. Recently, Lan et al. (Discuss Math Graph Theory 39: 805–814, 2019) determined the exact value of \(ex(n,2P_7)\) . Motivated by their result, we show that \(ex(n,2P_9) = max\{{(7n+153+r(r-8))/2},7n-27\}\) for all \(n\ge 18\) , where r is the remainder of \(n-17\) when divided by 8.
      PubDate: 2022-04-15
       
  • The Rigidity of Infinite Graphs II

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      Abstract: Abstract Inductive constructions are established for countably infinite simple graphs which have minimally rigid locally generic placements in \({{\mathbb{R}}}^2\) . This generalises a well-known result of Henneberg for generically rigid finite graphs. Inductive methods are also employed in the determination of the infinitesimal flexibility dimension of countably infinite graphs associated with infinitely faceted convex polytopes in \({{\mathbb{R}}}^3\) . In particular, a generalisation of Cauchy’s rigidity theorem is obtained.
      PubDate: 2022-04-13
       
  • The Ihara-Zeta Function and the Spectrum of the Join of Two Semi-Regular
           Bipartite Graphs

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      Abstract: Abstract In this paper, using matrix techniques, we compute the Ihara-zeta function and the number of spanning trees of the join of two semi-regular bipartite graphs. Furthermore, we show that the spectrum and the Ihara-zeta function of the join of two semi-regular bipartite graphs can determine each other.
      PubDate: 2022-04-07
       
  • A Note on Exact Minimum Degree Threshold for Fractional Perfect Matchings

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      Abstract: Abstract Rödl, Ruciński, and Szemerédi determined the minimum \((k-1)\) -degree threshold for the existence of fractional perfect matchings in k-uniform hypergrahs, and Kühn, Osthus, and Townsend extended this result by asymptotically determining the d-degree threshold for the range \(k-1>d\ge k/2\) . In this note, we prove the following exact degree threshold: let k, d be positive integers with \(k\ge 4\) and \(k-1>d\ge k/2\) , and let n be any integer with \(n\ge 2k(k-1)+1\) . Then any n-vertex k-uniform hypergraph with minimum d-degree \(\delta _d(H)>{n-d\atopwithdelims ()k-d} -{n-d-(\lceil n/k\rceil -1)\atopwithdelims ()k-d}\) contains a fractional perfect matching. This lower bound on the minimum d-degree is best possible. We also determine the minimum d-degree threshold for the existence of fractional matchings of size s, where \(0<s\le n/k\) (when \(k/2\le d\le k-1\) ), or with s large enough and \(s\le n/k\) (when \(2k/5<d<k/2\) ).
      PubDate: 2022-04-06
       
  • Stability on Matchings in 3-Uniform Hypergraphs

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      Abstract: Abstract Given a positive integer r, let \([r]=\{1,\ldots ,r\}\) . Let n, m be positive integers such that n is sufficiently large and \(1\le m\le \lfloor n/3\rfloor -1\) . Let H be a 3-graph with vertex set [n], and let \(\delta _1(H)\) denote the minimum vertex degree of H. The size of a maximum matching of H is denoted by \(\nu (H)\) . Kühn, Osthus and Treglown (2013) proved that there exists an integer \(n_0\in \mathbb {N}\) such that if H is a 3-graph with \(n\ge n_0\) vertices and \(\delta _1(H)>{n-1\atopwithdelims ()2}-{n-m\atopwithdelims ()2}\) , then \(\nu (H)\ge m\) . In this paper, we show that there exists an integer \(n_1\in \mathbb {N}\) such that if \( V(H) \ge n_1\) , \(\delta _1(H)>{n-1\atopwithdelims ()2}-{n-m\atopwithdelims ()2}+3\) and \(\nu (H)\le m\) , then H is a subgraph of \(H^*(n,m)\) , where \(H^*(n,m)\) is a 3-graph with vertex set [n] and edge set \(E(H^*(n,m))=\{e\subseteq [n]: e =3 \text{ and } e\cap [m] \ne \emptyset \}\) . The minimum degree condition is best possible.
      PubDate: 2022-04-06
       
  • Avoiding and Extending Partial Edge Colorings of Hypercubes

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      Abstract: Abstract We consider the problem of extending and avoiding partial edge colorings of hypercubes; that is, given a partial edge coloring \(\varphi \) of the d-dimensional hypercube \(Q_d\) , we are interested in whether there is a proper d-edge coloring of \(Q_d\) that agrees with the coloring \(\varphi \) on every edge that is colored under \(\varphi \) ; or, similarly, if there is a proper d-edge coloring that disagrees with \(\varphi \) on every edge that is colored under \(\varphi \) . In particular, we prove that for any \(d\ge 1\) , if \(\varphi \) is a partial d-edge coloring of \(Q_d\) , then \(\varphi \) is avoidable if every color appears on at most d/8 edges and the coloring satisfies a relatively mild structural condition, or \(\varphi \) is proper and every color appears on at most \(d-2\) edges. We also show that \(\varphi \) is avoidable if d is divisible by 3 and every color class of \(\varphi \) is an induced matching. Moreover, for all \(1 \le k \le d\) , we characterize for which configurations consisting of a partial coloring \(\varphi \) of \(d-k\) edges and a partial coloring \(\psi \) of k edges, there is an extension of \(\varphi \) that avoids \(\psi \) .
      PubDate: 2022-04-04
       
  • Improved Monochromatic Double Stars in Edge Colorings

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      Abstract: Abstract We give a slight improvement on the size of a monochromatic double star we can guarantee in every r-coloring of the edges of \(K_n\) .
      PubDate: 2022-03-28
       
  • Predominating a Vertex in the Connected Domination Game

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      Abstract: Abstract The connected domination game is played just as the domination game, with an additional requirement that at each stage of the game the vertices played induce a connected subgraph. The number of moves in a D-game (an S-game, resp.) on a graph G when both players play optimally is denoted by \(\gamma _\mathrm{cg}(G)\) ( \(\gamma _\mathrm{cg}'(G)\) , resp.). Connected Game Continuation Principle is established as a substitute for the classical Continuation Principle which does not hold for the connected domination game. Let G x denote the graph G together with a declaration that the vertex x is already dominated. The first main result asserts that if G is a graph with \(\gamma _\mathrm{cg}(G) \ge 3\) and \(x \in V(G)\) , then \(\gamma _\mathrm{cg}(G x) \le 2 \gamma _\mathrm{cg}(G) - 3\) and the bound is sharp. The second main theorem states that if G is a graph with \(n(G) \ge 2\) and \(x \in V(G)\) , then \(\gamma _\mathrm{cg}(G x) \ge \left\lceil \frac{1}{2} \gamma _\mathrm{cg}(G) \right\rceil\) and the bound is sharp. Graphs G and their vertices x for which \(\gamma _\mathrm{cg}'(G x) = \infty\) holds are also characterized.
      PubDate: 2022-03-25
       
  • Improved Bounds on the k-tuple (Roman) Domination Number of a Graph

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      Abstract: Abstract In Henning and Jafari Rad (Graphs Combin, 37: 325–336, 2021), several new probabilistic upper bounds are given on the k-tuple domination number, k-domination number, Roman domination number, and Roman k-domination number of a graph using the well-known Brooks’ Theorem for vertex coloring, improving all of previous given bounds for the above domination variants. In this paper, we use the well-known Turán’s Theorem, and give a slight improvement of all above given bounds.
      PubDate: 2022-03-23
       
  • On 2-Factors Splitting an Embedded Graph into Two Plane Graphs

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      Abstract: We investigate 2-planarizing 2-factors, i.e. 2-factors of embedded graphs so that cutting along the cycles of the 2-factor we get two plane graphs where the cycles of the 2-factors are a spanning set of face boundaries in each of the graphs. We will give necessary criteria for an abstract graph to have an embedding with a 2-planarizing 2-factor as well as necessary criteria for embedded graphs to have such a 2-factor. Along the way, we discuss to which degree classical results from planar hamiltonicity theory can be extended in our framework. In addition we present computational results on how common 2-planarizing 2-factors are in small cubic graphs.
      PubDate: 2022-03-23
       
  • Disjoint Cycles of Different Lengths in 3-Regular Digraphs

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      Abstract: Abstract In 2012, Henning and Yeo have posed the conjecture that a bipartite 3-regular digraph contains two disjoint cycles of different lengths, and Tan has proved that a 3-regular bipartite digraph, which possesses a cycle factor with at least two cycles, does indeed have two disjoint cycles of different lengths. In this paper, we prove that every 3-regular digraph, which possesses a cycle factor with at least three cycles, contains two disjoint cycles of different lengths, except for the digraph that is isomorphic to the \(D_{2n}^2\) ( \(n\ge 3\) ).
      PubDate: 2022-03-18
       
 
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