The fixed point method has been applied for the first time, in proving the stability results for
functional equations, by Baker (1991); he used a variant of Banach′ s fixed point theorem …

The issue of Ulam's type stability of an equation is understood in the following way: when a
mapping which satisfies the equation approximately (in some sense), it is" close" to a …

We consider a new approach to approximate stability analysis for a tri-additive functional
inequality and to obtain the optimal approximation for permuting tri-derivations and tri …

The aim of this article is to prove a fixed point theorem in 2-Banach spaces and show its
applications to the Ulam stability of functional equations. The obtained stability results …

Beginning around the year 1980, the topic of approximate homomorphisms and derivations
and their stability theory in the field of functional equations and inequalities was taken up by …

In this paper, we introduce $ n $-variables mappings which are cubic in each variable. We
show that such mappings satisfy a functional equation. The main purpose is to extend the …

This is a survey paper concerning stability results for the linear functional equation in single
variable. We discuss issues that have not been considered or have been treated only briefly …

The theory of Ulam stability was initiated by a problem raised in 1940 by S. Ulam and
concerning approximate solutions to the equation of homomorphism in groups. It is …

We obtain some results on approximate solutions of the generalised linear functional
equation for functions mapping a normed space into a normed space. We show that, under …

In this paper, we unify the system of functional equations defining a multi-Jensen-quadratic
mapping to a single equation. Using a fixed point theorem, we study the generalized Hyers …