A fixed points approach to stability of the Pexider equation

B. Bouikhalene, E. Elqorachi, J. M. Rassias

Using the fixed point theorem we establish the Hyers-Ulam-Rassias stability of the generalized Pexider functional equation
1/|K| ∑kϵ K f(x+k.y)=g(x)+h(y), x, y ϵ E
from a normed space E into a complete β-normed space F, where K is a finite abelian subgroup of the automorphism group of the group (E,+). 

Tbilisi Mathematical Journal, Vol. 7(2) (2014), pp. 95-110