Madjid Eshaghi Gordji

STABILITY OF A FUNCTIONAL EQUATION DERIVING FROM QUARTIC AND ADDITIVE FUNCTIONS

In this paper, we obtain the general solution and the generalized Hyers-Ulam Rassias stability of the functional equation f(2x + y) + f(2x - y) = 4(f(x + y) + f(x - y)) - (f(2y) - 2f(y)) + 2f(2x) - 8f(x).

Coupled fixed point theorems for contractions in intuitionistic fuzzy normed spaces

Abstract Following the definition of coupled fixed point [T. G. Bhaskar, V. Lakshmikantham, Fixed point theorems in partially ordered metric spaces and applications, Nonlinear Anal. 65 (2006) 1379–1393], we prove a coupled fixed point theorem for contractive mappings in partially complete intuitionistic fuzzy normed spaces.

A generalization of Geraghty's theorem in partially ordered metric spaces and applications to ordinary differential equations

The purpose of this article is to present some fixed point theorems for generalized contraction in partially ordered complete metric spaces. As an application, we give an existence and uniqueness for the solution of an initial-boundary-value problem.2000 Mathematics Subject Classification: 47H10; 54H25; 34B15.

Perspectives of matrix convex functions.

In this paper, we generalize the main results of [Effros EG, (2009) Proc Natl Acad. Sci USA 106:1006–1008]. Namely, we provide the necessary and sufficient conditions for jointly convexity of perspective functions and generalized perspective functions.

On the Stability of Quadratic Double Centralizers and Quadratic Multipliers: A Fixed Point Approach

We prove the superstability of quadratic double centralizers and of quadratic multipliers on Banach algebras by fixed point methods. These results show that we can remove the conditions of being weakly commutative and weakly without order which are used in the work of M. E. Gordji et al. (2011) for Banach algebras.

Fixed point results for generalized ( α , ψ ) -Meir-Keeler contractive mappings and applications

In this paper, we introduce a new type of a generalized-(α,ψ)-Meir-Keeler contractive mapping and establish some interesting theorems on the existence of fixed points for such mappings via admissible mappings. Applying our results, we derive fixed point theorems in ordinary metric spaces and metric spaces endowed with an arbitrary binary relation.MSC:47H10, 54H25.

Coupled common fixed point theorems for mixed weakly monotone mappings in partially ordered metric spaces

In this paper, we introduce the concept of a mixed weakly monotone pair of mappings and prove some coupled common fixed point theorems for a contractive-type mappings with the mixed weakly monotone property in partially ordered metric spaces. Our results are generalizations of the main results of Bhaskar and Lakshmikantham and Kadelburg et al.Mathematics Subject Classification 2000: 54H25.

N -fixed point theorems for nonlinear contractions in partially ordered metric spaces

In present paper we introduce the concept of a new g-monotone mapping and define the notions of n-fixed point and n-coincidence point and prove some related theorems for nonlinear contractive mappings in partially ordered complete metric spaces. Our results are generalization of the main results of Lakshmikantham and Ćirić (Nonlinear Anal. 70:4341-4349, 2009) and include several recent developments. Moreover, we give an example to support our results.MSC:Primary 47H10; secondary 54H25; 34B15.

Common fixed point theorems for (ψ, φ)-weak nonlinear contraction in partially ordered sets

The purpose of this article is to present some fixed point theorems for (ψ, φ)-weak contractive mappings in a complete metric space endowed with a partial order. As an application of the main result, we give an existence theorem for the solution of a periodic boundary value problem.2000 Mathematics Subject Classification: 47H10.

Jensen-type inequalities for Sugeno integral

In this paper, the classical Jensen inequalities for concave function ź, i.e., ź ( ź f ( x ) d µ ) ź ź ź ( f ) d µ and ź ( ź i = 1 n λ i x i ) ź ź i = 1 n λ i ź ( x i ) , are adapted for the Sugeno integral using the notion of the supergradient. Moreover, we give some modifications of previous results of Roman-Flores etźal. concerning Jensen-type inequalities for Sugeno integral. Some examples in the framework of the Lebesgue measure and counting measure to illustrate the results are presented.