Themistocles M. Rassias

Combines comprehensive coverage of both past and current research. Deals with representations and approximations of functions in several variables in terms of finite sums of factor functions' results in a lesser number of variables. One of the basic questions treated is closely connected with the 13th problem of David Hilbert which concerns the solvability of algebraic equations.

This volume provides a study of some of the well-known inequalities in classical mathematical analysis. Subjects dealt with include: Hardy-Littlewood-type inequalities, Hardy's and Carleman's inequalities, Lyapunov inequalities, Shannon's and related inequalities, generalised Shannon functional inequality, operator inequalities associated with Jensen's inequality, weighted Lp-norm inequalities in convolutions, Heyers-Ulam stability of functional equations in connection with classical inequalities, inequalities for polynomial zeros, as well as applications in a number of problems of pure and applied mathematics. Audience: This book will be of interest to mathematicians and graduate students whose work involves real functions, functions of a complex variable, functional analysis, approximation theory, numerical analysis, and other subjects of mathematical analysis.

This volume provides an extensive study of some of the most important topics of current interest in functional equations and inequalities. Subjects dealt with include: a Pythagorean functional equation, a functional definition of trigonometric functions, the functional equation of the square root spiral, a conditional Cauchy functional equation, an iterative functional equation, the Hille-type functional equation, the polynomial-like iterative functional equation, distribution of zeros and inequalities for zeros of algebraic polynomials, a qualitative study of Lobachevsky's complex functional equation, functional inequalities in special classes of functions, replicativity and function spaces, normal distributions, some difference equations, finite sums, decompositions of functions, harmonic functions, set-valued quasiconvex functions, the problems of expressibility in some extensions of free groups, Aleksandrov problem and mappings which preserve distances, Ulam's problem, stability of some functional equation for generalized trigonometric functions, Hyers-Ulam stability of Hosszú's equation, superstability of a functional equation, and some demand functions in a duopoly market with advertising. Audience: This book will be of interest to mathematicians and graduate students whose work involves real functions, functions of a complex variable, functional analysis, integral transforms, and operational calculus.