26.07.2017

 Print Edition: ISSN 1584 - 2851 Online Edition: ISSN 1843 - 4401 Carpathian J. Math. is a category A journal in the CNCSIS classification Impact Factor 2015:     0.610 Current rejection rate: 80 % RSS
Contents (PDF)
Vol. 27 (2011), No. 1, 15 March 2011
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 On a second order differential equation with piecewise constant mixed arguments Author: H. Bereketoglu / G. Seyhan / F. Karakoc Abstract: We prove the existence and uniqueness of solutions of a class of second order differential equations with piecewise constant mixed arguments and we show that the zero solution of Eq. (1.1) is a global attractor. Also, we study some properties of solutions of Eq. (1.1) such as oscillation, nonoscillation, and periodicity.PDF | No. of downloads: 208 Stability of Picard iteration for contractive mappings satisfying an implicit relation Author: Vasile Berinde Abstract: We obtain new and very general stability results for Picard iteration associated to self operators satisfying an implicit relation. Our stability results unify, extend, generalize, enrich and complement a multitude of related stability results from recent literature.PDF | No. of downloads: 204 Generalized Weyl's theorems for polaroid operators Author: C. Carpintero / D. Munoz / E. Rosas / O. Garcia / J. Sanabria Abstract: In this paper we establish necessary and sufficient conditions on bounded linear operators for which generalized Weyl's theorem, or generalized $a$-Weyl theorem, holds. We also consider generalized Weyl's theorems in the framework of polaroid operators and obtain improvements of some results recently established in [20] and [29]. PDF | No. of downloads: 207 On controllability for a class of second-order differential inclusions Author: Aurelian Cernea Abstract: By using a suitable fixed point theorem a sufficient condition for controllability is obtained for a Sturm-Liouville type differential inclusion in the case when the right hand side has convex values.PDF | No. of downloads: 159 Positive periodic solutions for systems of second order differential equations Author: Vasile Dincuță-Tănase Abstract: In this paper we seek for positive periodic solutions for a system of second order differential equations using a vector version of Krasnoselskii's Fixed Point Theorem in Cones. This makes possible that the nonlinear term of the system have different behaviors both in components and variables.PDF | No. of downloads: 141 Analytical investigation of beam deformation equation using perturbation, homotopy perturbation, variational iteration and optimal homotopy asymptotic methods Author: F. Farrokhzad / P. Mowlaee / A. Barari / A. J. Choobbasti / H. D. Kaliji Abstract: The beam deformation equation has very wide applications in structural engineering. As a differential equation, it has its own problem concerning existence, uniqueness and methods of solutions. Often, original forms of governing differential equations used in engineering problems are simplified, and this process produces noise in the obtained answers. This paper deals with solution of second order of differential equation governing beam deformation using four analytical approximate methods, namely the Homotopy Perturbation Method (HPM), Variational Iteration Method (VIM) and Optimal Homotopy Asymptotic Method (OHAM). The comparisons of the results reveal that these methods are very effective, convenient and quite accurate to systems of non-linear differential equation. PDF | No. of downloads: 158 Some applications of CHEVIE to the theory of algebraic groups Author: Meinolf Geck Abstract: The computer algebra system CHEVIE is designed to facilitate computations with various combinatorial structures arising in Lie theory, like finite Coxeter groups and Hecke algebras. We discuss some recent examples where CHEVIE has been helpful in the theory of algebraic groups, in questions related to unipotent classes, the Springer correspondence and Lusztig families.PDF | No. of downloads: 189 Full access PDF | Boundary value problems for nonlinear systems with generalized second-order differences Author: Rodica Luca Abstract: In a real Hilbert space, we investigate the existence and uniqueness of the solutions for two classes of infinite nonlinear systems with generalized second-order differences, one of them subject to a boundary condition. Some applications to nonlinear differential systems with monotone operators are also presented.PDF | No. of downloads: 134 Sufficient conditions for the existence of some nonoscillatory solutions of third-order nonlinear differential equations Author: Ivan Mojsej / Alena Tartalova Abstract: The aim of this paper is to study the asymptotic behavior of solutions of nonlinear differential equations of the third-order with quasiderivatives. In particular, we state the sufficient conditions ensuring the existence of some nonoscillatory solutions with a specified asymptotic property as $t$ tends to infinity. The basic tool used in proving our results is the classical Banach contraction mapping principle.PDF | No. of downloads: 154 On a regularization technique for Kovarik-like approximate orthogonalization algorithms Author: Aurelian Nicola / Constantin Popa / Ulrich Rude Abstract: In this paper we consider four versions of Kovarik's iterative orthogonalization algorithm, for approximating the minimal norm solution of symmetric least squares problems. Although the theoretical convergence rate of these algorithms is at least linear, in practical applications we observed that a too big number of iterations can dramatically deteriorate the already obtained approximation. In this respect we analyse the above mentioned Kovarik-like methods according to the modifications they make on the machine zero'' eigenvalues of the problem's (symmetric) matrix. We establish a theoretical almost optimal formula for the number of iterations necessary to obtain an enough accurate approximation, as well as to avoid the above mentioned troubles. Experiments on collocation discretization of a Fredholm first kind integral equation illustrate the efficiency of our considerations.PDF | No. of downloads: 202 n-th relative nilpotency degree and relative n-isoclinism classes Author: Rashid Rezaei / Francesco G. Russo Abstract: P. Hall introduced the notion of isoclinism between two groups more than 60 years ago. Successively, many authors have extended such a notion in different contexts. The present paper deals with the notion of relative n-isoclinism, given by N. S. Hekster in 1986, and with the notion of n-th relative nilpotency degree, recently introduced in literature.PDF | No. of downloads: 150 Continuous dependence on a parameter of the countable fractal interpolation function Author: Nicolae-Adrian Secelean Abstract: In this paper we will show that, if a countable interpolation data depends continuously on a parameter and some proper continuity conditions are fulfilled, then its associated attractor and the corresponding countable fractal interpolation function depends also continuously on the respective parameter. An example in R^2 is given.PDF | No. of downloads: 153 On approximating curves associated with nonexpansive mappings Author: Francesca Vetro Abstract: PDF | No. of downloads: 234

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