Stability of the Cauchy equation in ordered fields.
Stability of the Cauchy functional equation in quasi-Banach spaces
Let X be a quasi-Banach space. We prove that there exists K > 0 such that for every function w:ℝ → X satisfying ||w(s+t)-w(s)-w(t)|| ≤ ε(|s|+|t|) for s,t ∈ ℝ, there exists a unique additive function a:ℝ → X such that a(1)=0 and ||w(s)-a(s)-sθ(log₂|s|)|| ≤ Kε|s| for s ∈ ℝ, where θ: ℝ → X is defined by for k ∈ ℤ and extended in a piecewise linear way over the rest of ℝ.
Stability of the Cauchy-Jensen functional equation in -algebras: a fixed point approach.
Stability of the Jensen-type functional equation in -algebras: a fixed point approach.
Stability of the Lobacevski equation.
Stability of trigonometric functional equations in generalized functions.
Stability problem of Ulam for Euler-Lagrange quadratic mappings.
Stability problems of quintic mappings in quasi--normed spaces.
Stability type results concerning the fundamental equation of information of multiplicative type
The paper deals with the stability of the fundamental equation of information of multiplicative type. It is proved that the equation in question is stable in the sense of Hyers and Ulam under some assumptions. This result is applied to prove the stability of a system of functional equations that characterizes the recursive measures of information of multiplicative type.
Strictly decreasing solutions of a class of iterative equations on the unit circle.
Superstability and stability of the pexiderized multiplicative functional equation.
Superstability for generalized module left derivations and generalized module derivations on a Banach module. II.
Superstability for generalized module left derivations and generalized module derivations on a Banach module. I.
Superstability of functional equations related to spherical functions
In this paper we prove stability-type theorems for functional equations related to spherical functions. Our proofs are based on superstability-type methods and on the method of invariant means.
Superstability of generalized derivations.
Superstability of generalized multiplicative functionals.
Superstability of multipliers and ring derivations on Banach algebras.
Superstability of some Pexider-type functional equation.
Ternary Jordan homomorphisms in -ternary algebras.
The additive approximation on a four-variate Jensen-type operator equation.