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Publisher: Springer-Verlag   (Total: 2355 journals)

 Afrika Matematika   [SJR: 0.248]   [H-I: 6]   [1 followers]  Follow         Hybrid journal (It can contain Open Access articles)    ISSN (Print) 1012-9405 - ISSN (Online) 2190-7668    Published by Springer-Verlag  [2355 journals]
• On neutrosophic soft lattices
• Authors: Vakkas Uluçay; Mehmet Şahin; Necati Olgun; Adem Kilicman
Pages: 379 - 388
Abstract: In this study, using the neutrosophic soft definitions, we define some new concept such as the neutrosophic soft lattice, neutrosophic soft sublattice, complete neutrosophic soft lattice, modular neutrosophic soft lattice, distributive neutrosophic soft lattice, neutrosophic soft chain then we study the relationship and observe some common properties.
PubDate: 2017-06-01
DOI: 10.1007/s13370-016-0447-7
Issue No: Vol. 28, No. 3-4 (2017)

• Numerical approximations of second order PDEs by boundary value methods
and the method of lines
• Authors: T. A. Biala; S. N. Jator; R. B. Adeniyi
Pages: 443 - 450
Abstract: In this work, we study the performance of boundary value methods (BVMs) discussed in Biala [10] and Biala et al. [11] in combination with the method of lines on second order PDEs. The method of lines converts the PDEs into an equivalent system of second order ordinary differential equations. The performance of BVMs on the semi-discretized system is evidenced by a few numerical examples.
PubDate: 2017-06-01
DOI: 10.1007/s13370-016-0458-4
Issue No: Vol. 28, No. 3-4 (2017)

• Some generalizations and refined Hardy type integral inequalities
• Authors: Khaled Mehrez
Pages: 451 - 457
Abstract: In this paper, by using Jensen’s inequality and Chebyshev integral inequality, some generalizations and new refined Hardy type integral inequalities are obtained. In addition, the corresponding reverse relation are also proved.
PubDate: 2017-06-01
DOI: 10.1007/s13370-016-0461-9
Issue No: Vol. 28, No. 3-4 (2017)

• Permanent of a rhotrix
• Authors: Abdulhadi Aminu; Muhammad Aminu; M. Z. Ringim
Pages: 481 - 491
Abstract: The permanent is a matrix function introduced (independently) by Cauchy and Binet and a number of results have so far been proved. In this paper, we extend the concept of permanent into rhotrix and also present a way of finding the permanent of a rhotrix and also establish some results. Rhotrix is an object that lies in some way between $$n\times n$$ dimensional matrices and $$( {2n-1})\times (2n-1)$$ dimensional matrices.
PubDate: 2017-06-01
DOI: 10.1007/s13370-016-0457-5
Issue No: Vol. 28, No. 3-4 (2017)

• A note on partial metric type structures and metric type structures
• Authors: Maggie Aphane; Seithuti Moshokoa
Pages: 549 - 553
Abstract: In the note we discuss partial metric type structures and present their basic properties as well as their relationship with metric type structures. As an application, fixed point theorems for a Lipschitzian map on this structures will be presented.
PubDate: 2017-06-01
DOI: 10.1007/s13370-016-0467-3
Issue No: Vol. 28, No. 3-4 (2017)

• A note on prime ring with generalized derivation
• Authors: Mohd Arif Raza; Nadeem Ur Rehman
Pages: 555 - 561
Abstract: Let R be a prime ring of characteristic different from two with center Z(R). In the present paper we study the case when a generalized derivation F associated with a nonzero derivation d of R satisfies $$[F([x, y]_k), [x, y]_k]\in Z(R)$$ for all x, y in some appropriate subset of R, where k is a fixed positive integer. We obtain a description of the structure of R and information on the form of F in terms of the standard identity $$s_4$$ and the multiplication by the specific element from the extended centroid.
PubDate: 2017-06-01
DOI: 10.1007/s13370-016-0465-5
Issue No: Vol. 28, No. 3-4 (2017)

• An iterative method for multivalued tempered Lipschitz hemicontractive
mappings
• Authors: M. E. Okpala
Pages: 595 - 604
Abstract: In this paper we introduce a new general class of multi-valued Lipschitz hemicontractive mappings. We then prove strong convergence theorems for finding a fixed point of the mapping using a new two steps averaged algorithm. The method used in the proof is new and enables us to systematically avoid so many strong assumptions in the contemporary literature. The theorems obtained generalize and improve many results in the literature.
PubDate: 2017-06-01
DOI: 10.1007/s13370-016-0468-2
Issue No: Vol. 28, No. 3-4 (2017)

• On multiplication operators acting on Köthe sequence spaces
• Authors: Julio C. Ramos-Fernández; Margot Salas-Brown
Pages: 661 - 667
Abstract: We present some characterizations for the multiplication operators $$M_u$$ with finite range when acts on any Köthe sequence spaces. we also characterize its compactness and Fredholmness. Our characterizations are presented in terms of certain properties of the zeros set and the support of the symbol u.
PubDate: 2017-06-01
DOI: 10.1007/s13370-016-0475-3
Issue No: Vol. 28, No. 3-4 (2017)

• Weakly invo-clean unital rings
• Authors: Peter V. Danchev
Abstract: We define and completely describe the structure of weakly invo-clean rings possessing identity. We show that these rings are clean but neither weakly nil-clean nor invo-clean, and thus they have some new exotic properties different to those established by Breaz et al. (J Algebra Appl 15, 2016) and Danchev (Commun Korean Math Soc 32:19–27, 2017), respectively.
PubDate: 2017-07-20
DOI: 10.1007/s13370-017-0515-7

• $$({\alpha ,\beta })$$ ( α , β ) -Intuitionistic fuzzy bi-ideals of
semigroups
• Authors: Saleem Abdullah; Shah Hussain
Abstract: In this article, a new generalization of intuitionsitic fuzzy bi-ideals of a semigroup considered so called $$(\alpha ,\beta )$$ -intuitionistic fuzzy bi-ideals, (1, 2)-ideals in a semigroup. We combine the notion of intuitionsitic fuzzy point and intuitionistic fuzzy sets to defined different types of intuitionsitic fuzzy bi-ideals of a semigroups. We investigate different properties of these notions and their relationships, particularly, we define $$(\in ,\in \vee q)$$ -intuitionistic fuzzy bi-ideals and (1, 2) ideals in semigroups.
PubDate: 2017-07-06
DOI: 10.1007/s13370-017-0501-0

• Studies on Cauchy problems for impulsive differential models involving
higher order Riemann–Liouville fractional derivatives
• Authors: Yuji Liu
Abstract: In this article, existence results of solutions of a class of boundary value problems of nonlinear singular multi-term fractional differential models with impulses on half line involving higher order Riemann–Liouville fractional derivatives are established. Our analysis rely on a well known fixed point theorems. Examples are presented to illustrate the main theorems.
PubDate: 2017-07-03
DOI: 10.1007/s13370-017-0505-9

• Well-posedness and energy decay for Timoshenko systems with discrete time

• Authors: Aissa Guesmia
Abstract: In this paper, we consider a vibrating system of Timoshenko-type in a bounded one-dimensional domain with discrete time delay and complementary frictional damping and infinite memory controls all acting on the transversal displacement. We show that the system is well-posed in the sens of semigroup and that, under appropriate assumptions on the weights of the delay and the history data, the stability of the system holds in case of the equal-speed propagation as well as in the opposite case in spite of the presence of a discrete time delay, where the decay rate of solutions is given in terms of the smoothness of the initial data and the growth of the relaxation kernel at infinity. The results of this paper extend the ones obtained by the present author and Messaoudi in (Acta Math Sci 36:1–33, 2016) to the case of presence of discrete delay.
PubDate: 2017-06-30
DOI: 10.1007/s13370-017-0514-8

• (Semi)topological quotient BCK-algebras
• Authors: N. Kouhestani; S. Mehrshad
Abstract: In this paper we study separation axioms and connected properties on (semi)topological quotient BCK-algebras. We bring some conditions which under a (semi)topological quotient BCK-algebra have at least one of the topological properties $$T_1,$$ Hausdorff, regular, normal, connected, locally connected, totally disconnected space.
PubDate: 2017-06-21
DOI: 10.1007/s13370-017-0513-9

• A priori analysis of multilevel finite volume approximation of 1D
convective Cahn–Hilliard equation
• Abstract: In this work, we analyze four finite volume methods for the nonlinear convective Cahn–Hilliard equation with specified initial condition and periodic boundary conditions. The methods used are: implicit one-level, explicit one-level, implicit multilevel and explicit multilevel finite volume methods. The existence and uniqueness of solution, convergence and stability of the finite volume solutions are proved. We compute $$L_2$$ - error and rate of convergence for all methods. We then compare the multilevel methods with the one-level methods by means of stability and CPU time. It is shown that the multilevel finite volume method is faster than the one-level method.
PubDate: 2017-06-21
DOI: 10.1007/s13370-017-0512-x

• Gorenstein FI -flat dimension and relative homology
• Authors: B. Vasudevan; R. Udhayakumar; C. Selvaraj
Abstract: In this paper, we study some properties and behavior of finite Gorenstein FI-flat dimension through the methods of relative homological algebra.
PubDate: 2017-06-16
DOI: 10.1007/s13370-017-0508-6

• Fourier-Bessel Dini Lipschitz functions in the space $$L_{\alpha ,n}^{2}$$
L α , n 2
• Authors: S. El Ouadih; R. Daher
Abstract: In this paper, using a generalized translation operator, we obtain an analog of Younis’s Theorem 5.2 in Younis (Int J Math Math Sci 9:301–312, 1986) for the generalized Fourier-Bessel transform for functions satisfying the Fourier-Bessel Dini Lipschitz condition in the space $$L_{\alpha ,n}^{2}$$ .
PubDate: 2017-06-14
DOI: 10.1007/s13370-017-0509-5

• A note on the lattice of fuzzy hyperideals of a hyperring
• Authors: D. Bayrak; S. Yamak
Abstract: Many studies have investigated lattices of fuzzy algebraic systems. One of them belongs to Borzooei et al. (Soft Comput 12:739–749, 2008) who found some properties of lattices of fuzzy algebraic structures. In this study, we solve the problem of finding necessary and sufficient conditions for distributivity and modularity of lattice of fuzzy hyperideals of a hyperring which was one of the open problems in Borzooei’s paper.
PubDate: 2017-06-13
DOI: 10.1007/s13370-017-0511-y

• Some new explicit values of Ramanujan–Selberg continued fraction
• Authors: Nipen Saikia; Chayanika Boruah
Abstract: We use Ramanujan’s mixed modular equations to evaluate some new values of the parameter $$J_n$$ involving Ramanujan’s theta-function $$f(-q)$$ . The values $$J_n$$ are then used to evaluate new explicit values of the Ramanujan–Selberg continued fraction.
PubDate: 2017-06-10
DOI: 10.1007/s13370-017-0507-7

• The partial r -Bell polynomials
• Authors: Miloud Mihoubi; Mourad Rahmani
Abstract: In this paper, we show that the r-Stirling numbers of both kinds, the r-Whitney numbers of both kinds, the r-Lah numbers and the r-Whitney-Lah numbers form particular cases of a family of polynomials forming a generalization of the partial Bell polynomials. We deduce the generating functions of several restrictions of these numbers. In addition, a new combinatorial interpretations is presented for the r-Whitney numbers and the r-Whitney-Lah numbers.
PubDate: 2017-06-09
DOI: 10.1007/s13370-017-0510-z

• Krasnosel’skii type fixed point theorems in ordered Banach spaces
• Authors: Amina Boucenna; Smaïl Djebali; Toufik Moussaoui
Abstract: The aim of this work is to present new abstract fixed point theorems in ordered Banach spaces and on Banach algebras. The main existence results generalize Krasnosel’skii’s fixed point theorem of compression and expansion to a class of $$\alpha$$ -homogeneous operators and monotone operators. Two applications to nonlinear Hammerstein integral equations, one of which is of fractional order, are provided together with a numerical example.
PubDate: 2017-06-07
DOI: 10.1007/s13370-017-0506-8

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