We present a survey of ideas and results stemming from the following stability problem of
SM Ulam. Given a group G 1, a metric group G 2 and ε> 0, find δ> 0 such that, if f: G 1→ G 2 …

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 …

The notion of stability of functional equations of several variables in the sense used here
had its origins more than half a century ago when S. Ulam posed the fundamental problem …

This book outlines the modern theory of functional equations and inequalities in several
variables. It consists of three parts. The first is devoted to additive and convex functions …

In this paper, we study the stability of functional equations that has its origins with SM Ulam,
who posed the fundamental problem 60 years ago and with DH Hyers, who gave the first …

On the Stability of Functional Equations in Banach Spaces Page 1 Ž . Journal of Mathematical
Analysis and Applications 251, 264284 2000 doi:10.1006rjmaa.2000.7046, available online …

Hyers-Ulam Stability of Linear Differential Equations of First Order Page 1 FLSEVI~R Available
online at www.sciencedirect.com 8 01E Nl~ll ~__~ DIR~C~Te Applied Mathematics Letters 17 …

The paper is a survey about Hyers—Ulam stability of functional equations and systems in
several variables. Its content is divided in the following chapters: 1.—Introduction. Historical …

Functional equations form a modern branch of mathematics. This book provides an
elementary yet comprehensive introduction to the field of functional equations and stabilities …

Let X be a complex Banach space and let I=(a, b) be an open interval. In this paper, we will
prove the generalized Hyers–Ulam stability of the differential equation ty′(t)+ αy (t)+ βtrx0 …