Ismat Beg

TOPSIS for Hesitant Fuzzy Linguistic Term Sets

We propose a new method to aggregate the opinion of experts or decision makers on different criteria, regarding a set of alternatives, where the opinion of the experts is represented by hesitant fuzzy linguistic term sets. An illustrative example is provided to elaborate the proposed method for selection of the best alternative.

COINCIDENCE POINT AND INVARIANT APPROXIMATION FOR MAPPINGS SATISFYING GENERALIZED WEAK CONTRACTIVE CONDITION

We prove the existence of coincidence point and common fixed point for mappings satisfying generalized weak contractive condition. As an application, related results on invariant approximation are derived. Our results generalize various known results in the literature.

The contraction principle for set valued mappings on a metric space with a graph

Let (X,d) be a metric space and F:X@?X be a set valued mapping. We obtain sufficient conditions for the existence of a fixed point of the mapping F in the metric space X endowed with a graph G such that the set V(G) of vertices of G coincides with X and the set of edges of G is E(G)={(x,y):(x,y)@?XxX}.

FIXED POINTS OF ASYMPTOTICALLY REGULAR MULTIVALUED MAPPINGS

Some results on fixed point of asymptotically regular multivalued mapping are obtained in metric spaces. The structure of common fixed points and coincidence points of a pair of compatible multivalued mappings is also discussed. Our work generalizes known results of Aubin and Siegel, Dube, Dube and Singh, Hardy and Rogers, Hu, Iseki, Jungck, Kaneko, Nadler, Ray and Shiau, Tan and Wong.

Random fixed points of random multivalued operators on polish spaces

RANDOM coincidence point theorems and random fixed point theorems are stochastic generalizations of classical coincidence point theorems and classical fixed point theorems. Random fixed point theorems for contraction mappings in Polish spaces were proved by Spacek [l] and Hans (2, 31. For a complete survey, we refer to Bharucha-Reid [4]. Itoh [5] proved several random fixed point theorems and gave their applications to random differential equations in Banach spaces. Recently, Sehgal and Singh [7], Papageorgiou [8] and Lin [9] have proved different stochastic versions of the well-known Schauder’s fixed point theorem. The aim of this paper is to prove various stochastic versions of Banach type fixed point theorems for multivalued operators. Section 2 is aimed at clarifying the terminology to be used and recalling basic definitions and facts. Section 3 deals with random coincidence point theorems for a pair of compatible random multivalued operators. The structure of common random fixed points of these operators is also studied. In Section 4, the existence of a common random fixed point of two random multivalued operators satisfying the Meir-Keeler type condition in Polish spaces is proved. Section 5 contains a random fixed point theorem for a pair of locally contractive random multivalued operators in .s-chainable Polish spaces. As an application, a theorem on random approximation is also obtained.

Robot selection by using generalized interval-valued fuzzy numbers with TOPSIS

Abstract The aim of this paper is to propose a method to aggregate the opinion of several decision makers on different criteria, regarding a set of alternatives, where the judgment of the decision makers are represented by generalized interval-valued trapezoidal fuzzy numbers. A generalized interval valued trapezoidal fuzzy number based technique for order preference by similarity to ideal solution is proposed that can reflect subjective judgment and objective information in real life. The weights of criteria and performance rating values of criteria are linguistic variables expressed as generalized interval-valued trapezoidal fuzzy numbers. Finally, an illustrative example is provided to elaborate the proposed method for the selection of a suitable robot according to our requirements.

Common fixed points of fuzzy maps

We prove common fixed point theorems for a pair of fuzzy mappings satisfying Edelstein, Alber and Guerr-Delabriere type contractive conditions in a metric linear space.

Common fixed points for maps on topological vector space valued cone metric spaces.

We introduced a notion of topological vector space valued cone metric space and obtained some common fixed point results. Our results generalize some recent results in the literature.

Random fixed point theorems for nonexpansive and contractive-type random operators on Banach spaces

The existence of random fixed points for nonexpansive and pseudocontractive random multivalued operators defined on unbounded subsets of a Banach space is proved. A random coincidence point theorem for a pair of compatible random multivalued operators is established.

Fixed Point in Topological Vector Space-Valued Cone Metric Spaces

We obtain common fixed points of a pair of mappings satisfying a generalized contractive type condition in TVS-valued cone metric spaces. Our results generalize some well-known recent results in the literature.