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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]
• Several two-point with memory iterative methods for solving nonlinear
equations
• Authors: Neha Choubey; Bhavna Panday; J. P. Jaiswal
Abstract: In this article, our main motivation is to present two-step with memory iterative methods for solving nonlinear equations. We attempted to convert the existing fourth-order without memory method into a with memory method. Further acceleration of convergence order is attained by means of different approximations of self-accelerating parameters. The parameters are calculated by Hermite interpolating polynomial and applied to accelerate the order of convergence of the without memory methods. In particular, the R-order of the proposed two-step with memory iterative method is increased without any additional calculations and it possesses high computational efficiency. At the end, the theoretical results are confirmed by considering different numerical examples. Numerical comparisons specify that the new family is efficient and give tough competition to some existing with memory iterative methods.
PubDate: 2018-02-07
DOI: 10.1007/s13370-018-0552-x

• Growth properties of vector valued Dirichlet series with complex exponents
• Authors: Akanksha; G. S. Srivastava
Abstract: Several authors have studied the growth properties of Dirichlet series and vector valued Dirichlet series (VVDS). Wen Ping Huang, Ju Hong Ning and Jin Tu have obtained various results by considering Dirichlet series with complex exponents. In this paper we obtainthe characterizations of order and type of vector valued Dirichlet series which generalize some well known results for growth of classical Dirichlet series. Further we have tried to study the growth properties of holomorphic vector valued Dirichlet series with complex exponents.
PubDate: 2018-02-07
DOI: 10.1007/s13370-018-0563-7

• A randomization device for estimating a rare sensitive attribute in
stratified sampling using Poisson distribution
• Authors: Tanveer A. Tarray; Housial P. Singh
Abstract: The nitty-gritty of this paper is to estimate the mean of the number of persons possessing a rare sensitive attribute by utilizing the Poisson distribution in stratified survey sampling. It is also shown that the proposed models are more efficient than Lee et al.’s (Statistics 47:575–589, 2013) models in both the cases when the proportion of persons possessing a rare unrelated attribute is known and that when it is unknown. Properties of the proposed randomized response models have been studied alongwith recommendations. Numerical illustrations are also given in support of the present study.
PubDate: 2018-02-07
DOI: 10.1007/s13370-018-0550-z

• Vague semiprime ideals of a $$\Gamma$$ Γ -semiring
• Authors: Y. Bhargavi; T. Eswarlal
Abstract: The concept of vague semiprime ideal of a $$\Gamma$$ -semiring with membership and non-membership functions taking the values in unit interval of real numbers are introduced and investigated some results.
PubDate: 2018-02-07
DOI: 10.1007/s13370-018-0551-y

• Gabriel topology related to Morita context of semirings
• Authors: Sujit Kumar Sardar; Krishanu Dey; Sugato Gupta
Abstract: In this paper we introduce the notion of Gabriel topology on semirings as well as on bisemimodules with unities. We also show that there is a lattice isomorphism between the Gabriel topologies on semirings and those on bisemimodules connected via Morita context.
PubDate: 2018-02-06
DOI: 10.1007/s13370-018-0547-7

• Propagation of waves in micropolar thermodiffusion elastic half-space
• Authors: Rajneesh Kumar; Sachin Kaushal; M. Marin
Abstract: The present paper is devoted to the study of propagation of plane waves in micropolar thermodiffusion elastic half-space in the context of generalized theories of thermoelasticity. The variations of amplitude ratios for plane waves (longitudinal wave, thermal wave and mass diffusive wave) are computed analytically and depicted graphically for longitudinal wave against the angle of incidence. The impact of relaxation times, micropolarity and diffusion have been studied. Some particular cases of interest are also deduced from the present investigation.
PubDate: 2018-02-05
DOI: 10.1007/s13370-018-0553-9

• Convergence theorems for finite families of $$\Phi$$ Φ -strongly
pseudocontractive mappings
• Authors: Ahmed A. Abdelhakim; R. A. Rashwan
Abstract: Suppose E is a Banach space with certain geometric properties and K is a nonempty closed convex subset of E. We prove that if a certain iterative sequence converges to the unique fixed point of a $$\Phi$$ -pseudocontractive mapping $$T:K\rightarrow K$$ under certain conditions then such an iterative process can be used to approximate the unique common fixed point of a finite family of $$\Phi$$ -pseudocontractive self mappings of K. Our results extend and generalize the results in Chidume (Proc Am Math Soc 120:2641–2649, 1994; Proc Am Math Soc 9:545–551, 1998), Huang (Comput Math Appl 36:13–21, 1998), Liu (Comput Math Appl 45:623–634, 2003), Osilike (Math Anal Appl 200:259–271, 1996; Nonlinear Anal 36:1–9, 1999) and many others.
PubDate: 2018-02-05
DOI: 10.1007/s13370-018-0549-5

• A new collocation formulation for the block Falkner-type methods with
trigonometric coefficients for oscillatory second order ordinary
differential equations
• Authors: J. O. Ehigie; S. A. Okunuga
Abstract: We consider a new class of modified block Falkner methods for the direct numerical integration of second-order initial value problems having periodic and oscillatory solutions. We will give a new collocation formulation different from that of Ramos et al. (J Comput Appl Math. https://doi.org/10.1016/j.cam.2015.12.018, 2016) for the coefficients of a modified block Falkner-type methods, which are frequency dependent. We give an example using our new approach to derive a practical method. Furthermore, the uniform general order conditions and the investigation of the stability properties are presented. Numerical experiments are carried out to illustrate the high effectiveness of the new methods compared with some recent methods in the literature.
PubDate: 2018-02-05
DOI: 10.1007/s13370-018-0558-4

• Uniform interior stabilization for the finite difference
fully-discretization of the 1-D wave equation
• Authors: H. El Boujaoui
Abstract: In this paper, we are interested to prove the uniform exponential decay of the energy for the finite difference fully-discretization of 1-D wave equation with an interior damping at $$\xi$$ . To this end, we decompose the fully discrete system into two subsystems: a conservative system, and a non conservative one. We show under a numerical hypothesis on $$\xi$$ that a uniform observability inequality holds for a conservative system, when the mesh size tends to zero using Fourier series technique. Then, we use the observability inequality to prove the uniform exponential decay of the energy for the damped system. Finally, we describe some numerical experiments to illustrate the exponential decay of the energy.
PubDate: 2018-02-05
DOI: 10.1007/s13370-018-0559-3

• Some operators on interval-valued hesitant fuzzy soft sets
• Authors: Manash Jyoti Borah; Bipan Hazarika
Abstract: The main aim of this paper is to introduced the operations “Union”, “Intersection” and four operators namely $$\tilde{O_1},\tilde{ O_2},\tilde{ O_3},\tilde{ O_4},$$ on interval-valued hesitant fuzzy soft sets and discuss some of their properties.
PubDate: 2018-02-02
DOI: 10.1007/s13370-018-0557-5

• On vector variational-like inequalities involving right
upper-Dini-derivative functions
• Authors: Anurag Jayswal; Shipra Singh
Abstract: In this paper, we introduce (weak) Stampacchia and Minty arcwise connected vector variational-like inequalities in the term of right upper-Dini-derivative and establish not only the relations of introduced inequalities with vector optimization problems but also the existence results, by using KKM-Fan theorem and Brouwer fixed point theorem. Examples are provided to illustrate the derived results.
PubDate: 2018-02-02
DOI: 10.1007/s13370-018-0548-6

• On function spaces with S-transform
• Authors: Baby Kalita; Sunil Kumar Singh
Abstract: For $$1 \le p,q <\infty$$ , we define the space $$W^{p,q}_{k_1,k_2}({\mathbb {R}}^n)$$ by means of the S-transform where $$k_1$$ and $$k_2$$ are weight functions on $${{\mathbb {R}}^n}$$ and $${\mathbb {R}}^n\times {\mathbb {R}}_0^n$$ , respectively. It is a Banach space with respect to a sum norm defined in this paper. Latter we discuss inclusion properties and obtain the dual space of $$W^{p,q}_{k_1,k_2}({\mathbb {R}}^n)$$ . Furthermore, we define the space $$\left( W^{p,q}_{k_1,k_2}\right) _{\xi }({\mathbb {R}}^n)$$ where $$\xi$$ is fixed and show that it is an essential Banach module over $$L^1_{k_1}({\mathbb {R}}^n)$$ .
PubDate: 2018-02-01
DOI: 10.1007/s13370-018-0546-8

• Semihypergroups associated with ternary relations
• Authors: S. Mirvakili; S. M. Anvariyeh; B. Davvaz
Abstract: Davvaz and Leoreanu-Fotea (Commun Algebra 38(10):3621–3636, 2010) studied binary relations on ternary semihypergroups. A ternary relation or triadic relation is a relation in which the number of places in the relation is three. Now, in this paper, instead of binary relations we consider ternary relations and instead of ternary semihypergroups we consider ordinary semihypergroups. Then, we study ternary relations on semihypergroups. In particular, we discuss some properties of compatible ternary relations on them.
PubDate: 2018-01-31
DOI: 10.1007/s13370-018-0554-8

• T -fuzzy KU -ideals of KU -algebras
• Authors: Tapan Senapati
Abstract: In this paper, using t-norm T, the notion of (imaginable) T-fuzzy KU-ideals of KU-algebras are introduced and investigated their related results. Images and preimages of KU-ideals under homomorphism are investigated. Using level subsets of KU-algebras, some characterization theorems are given. The Cartesian product and T-product of T-fuzzy KU-ideals of KU-algebras are discussed.
PubDate: 2018-01-31
DOI: 10.1007/s13370-018-0561-9

• Coefficient estimates for a subclass of parabolic bi-starlike functions
• Authors: Serap Bulut
Abstract: In this paper, we introduce a new subclass of analytic and bi-univalent functions in the open unit disk $$\mathbb {U}$$ . For functions belonging to this class, we obtain initial coefficient bounds and Fekete–Szegö inequality.
PubDate: 2018-01-30
DOI: 10.1007/s13370-018-0543-y

• On the structure of isoclinism classes of the non-commuting graphs
• Authors: B. Tolue; A. Rafiei; A. Erfanian
Abstract: In this paper, we introduce the new concept isoclinism of two non-commuting graphs. We describe it with this hope to determine the properties of the graph with large number of vertices and edges more easier by use of its smaller correspondence graph in its isoclinic class. In 1939, Hekster classified the groups by n-isoclinism which was weaker than isomorphism, where n is a positive integer. The abelian groups are in the same class by group-isoclinism, although their intrinsic properties are not the same. The notion of isoclinic groups is the inspiration to define the isoclinism of two graphs. The isoclinism of two graphs is a pair of significant special isomorphism between the quotient graphs of the given graphs. We observe that all complete 3-partite non-commuting graphs are in the same isoclinic class and the non-commuting graph associated to the dihedral group of order 8, $$D_{8}$$ is the representative of this class.
PubDate: 2018-01-29
DOI: 10.1007/s13370-018-0544-x

• Underlining some mathematical and physical aspects about the concept of
motion in general relativity
• Authors: Elmo Benedetto; Fabiano Feleppa
Abstract: The Einstein initial foundations of general relativity have to do with his great intuition and they are not clear as it is for special relativity. As has been widely emphasized, for example, in the book of Ohanian and Ruffini, the very name of the theory indicates a misconception. Despite this, the high school textbooks (at least the Italian ones) and books of scientific divulgation introduce the Einstein gravitational theory still following the initial approach leading, in our opinion, to misinterpretations. A careful student, for example, immediately asks: it is not true that the Earth rotates because I can consider it at rest thanks to general relativity theory. The relativity of motion is trivial in mathematics while it has deep meaning in physics and it is not sufficiently analyzed. Similarly, the arbitrary choice of the origin and the perfect equivalence between all coordinate systems are mathematical properties satisfied by general relativity and students can confuse it with physical equivalence between reference systems that have a deeper meaning and the Einstein theory does not verify it. Gravitational force does not exist and this is the real core of Einsteinian revolution. As happens in Newtonian physics and Special Relativity, also in general relativity the relative motions are the geodesic motions with the difference that spacetime can be curved and geodesics may not be a straight line. Similarly, in general relativity forces cause non-geodesic motion. Geodesic and non-geodesic are tensorial properties and for this reason they are absolute.
PubDate: 2018-01-24
DOI: 10.1007/s13370-018-0545-9

• Radiative heating of a glass plate: the semi-discrete problem (second
revision)
• Authors: Luc Paquet
Abstract: In a preceding paper (MSIA, 2012), we have studied the radiative heating of a glass plate. We have proved existence and uniqueness of the solution. Here, we want to study the semi-discrete problem and to prove a priori error estimates. Previously, in that purpose, we have to study the regularity of the solution to the exact problem and of its time derivative. A very important property, Proposition 13, is remarked concerning our elliptic projection, the milestone in deriving the a priori error estimates. A numerical test corroborating our theoretical a priori bounds is given.
PubDate: 2018-01-24
DOI: 10.1007/s13370-018-0542-z

• Dynamical analysis and consistent numerics for a delay model of viral
infection in phytoplankton population
• Authors: A. S. Hassan
Abstract: In this article, the effects of time delay and carrying capacity in the dynamics of viral phytoplankton and consistence numerics are studied. Basic properties and stabilities of equilibria are rigorously analyzed and conditions for stability switches are found. A dynamically consistent nonstandard finite difference scheme for the continuous delay model is designed to verify the results and reveal some interesting features of the model. Some ecological implications and interpretations are provided.
PubDate: 2018-01-04
DOI: 10.1007/s13370-017-0541-5

• A note on automorphisms of finite B -algebras
• Authors: Rasoul Soleimani
Abstract: In this paper, we introduce the notion of a central B-automorphism of a finite B-algebra. Also some properties of a finite B-algebra and B-automorphism algebra are investigated.
PubDate: 2017-12-19
DOI: 10.1007/s13370-017-0540-6

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