Volume 22, No. 1 (2012)

Articles

WELL-POSEDNESS AND PERIODIC POINT PROPERTY OF MAPPINGS SATISFYING A RATIONAL INEQUALITY IN AN ORDERED COMPLEX VALUED METRIC SPACE
M. ABBAS, B. FISHER, T. NAZIR

Azam, Fisher and Khan [A. Azam, B. Fisher and M. Khan, Common fi xed point theorems in complex valued metric spaces, Numerical Functional Analysis and Optimization, 32(3)(2011), 243-253] introduced a notion of complex valued metric space and obtained common fixed point result for mappings in the context of complex valued metric spaces. In this paper, employing the concept of weakly increasing mappings, the existence of common fixed points is obtained in an ordered complex valued metric space. We apply our results to study well-posedness of a common fixed point problem for two rational type contractive mappings and a periodic point property of mapping involved therein.

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GENERAL RANDERS MECHANICAL SYSTEMS
OTILIA LUNGU, VALER NIMINET

The general Randers spaces were introduced by R. Miron [2]. These are some generalizations of Randers spaces denoted GRn = (M; F + β ), equipped with the Lorentz nonlinear connection. In the present paper we de ne the General Randers Mechanical System as a triple (M; T; Fe), where T is the energy of the Rn space. We obtain the expressions for the curvature and the torsion of GRn and we give the formula for the local coecients of the canonical connection.

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FIXED POINT THEOREMS IN FUZZY METRIC SPACES THROUGH WEAK COMPATIBILITY
SEEMA MEHRA, RENU CHUGH

We prove a common fi xed point theorem for six self-maps on a complete fuzzy metric space that generate some compatible and weakly compatible pairs of maps. Our result extends and uni es corresponding fi xed point theorems of Sessa [9], Jungck [5], [6], Singh and Chauhan [10], that were proved for commuting and weakly commuting self maps of metric spaces or of probabilistic metric spaces.

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CALCULUS WITH WEAK UPPER GRADIENTS BASED ON BANACH FUNCTION SPACES
MARCELINA MOCANU

In this paper we extend some results regarding the properties of weak upper gradients, from the cases when B is an Orlicz space or a Lorentz space to the general case of a Banach function space. We provide methods to cut and paste B-weak upper gradients and give extensions to the case of B-weak upper gradients for the product rule and the chain rule. These results require no additional assumptions on the Banach function space B. We also prove the existence of a norm minimizing B-weak upper gradient for a function possessing at least one B -weak upper gradient that belongs to B,under the assumption that B is reflexive or B has an absolutely continuous norm. If in addition the norm of B is strictly monotone, it turns out that a norm minimizing B-weak upper gradient of a function is also minimal pointwise μ-almost everywhere among all the B-weak upper gradients of that function.

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NOTE ON α-COMPACT FUZZY TOPOLOGICAL SPACES
M. N. MUKHERJEE, R. P. CHAKRABORTY, A. BHATTACHARYYA

It is widely accepted that one of the most satisfactory generalizations of the concept of compactness to fuzzy topological spaces is α-compactness, first initiated by Gantner et al.[3], followed by further investigations by many others. In this article, we propose to characterize the said notion of α-compactness in terms of ordinary nets and power-set lters, and this seems to be quite a new approach to the study of α -compactness.

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ON THE LOCALLY MINKOWSKI GL<sup>n</sup> SPACE
VALER NIMINEȚ, OTILIA LUNGU

We continue the investigations of generalized Lagrangian mechanical system [5] with the study of the GL-metric when the Finsler space Fn is a locally Minkowski space. Moreover we replace the nonlinear connection with a new one.

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(E.A) PROPERTY AND ALTERING DISTANCE IN METRIC SPACES
VALERIU POPA, ALINA-MIHAELA PATRICIU

In this paper a general fi xed point theorem for mappings satisfying an implicit relation is proved for two weakly compatible mappings which have property (E.A), which generalize the main results from [1] and [14]. As a consequence a fixed point theorem for mappings satisfying an implicit contractive condition of integral type is obtained.

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A GENERAL FIXED POINT THEOREM FOR OCCASIONALLY WEAKLY COMPATIBLE MAPPINGS AND APPLICATIONS
VALERIU POPA

In this paper a general fi xed point theorem for two pairs of owc mappings satisfying an implicit relation using a generalization of the notion of distance introduced in [4], without triangle inequality and symmetry is proved. As application some results in quasi - metric and G - metric spaces are obtained. For two mappings we obtain some similar results to Theorems 2.1, 2.2, 2.3 [4].

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N-SUBALGEBRAS AND N-FILTERS IN CI-ALGEBRAS
A. REZAEI, A. BORUMAND SAEID

In this paper, we introduce the notions of N-subalgebras and N-fi lters in CI-algebras and give a number of their properties. The relationship between N-subalgebras and N-fi lters is also investigated.

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THE SEMILOCAL CONVERGENCE OF THE CONVEX ACCELERATION OF WHITTAKER'S METHOD
RALUCA ANAMARIA (POMIAN) SĂLĂJAN

In this article we study the convex acceleration of Whittaker's iterative method for approximating the roots of a real function of real argument, that is two times di erentiable and has a nonvanishing fi rst order derivative. We prove a semilocal convergence theorem for this method and we give a numerical example which illustrates this theorem.

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