Generalized Ulam-Hyers stability of a general mixed AQCQ-functional equation in multi-Banach spaces: a fixed point approach

Abstract

Using the fixed point method, we investigate the generalized Hyers-Ulam stability of the general mixed additive-quadratic-cubic-quartic functional equation $f(x + ny)+ f(x − ny) = n^2 f (x + y)+ n^2 f (x − y)+2(1− n^2) f (x)+ frac{n^4 −n^2} {12}[ f (2y)+ f (−2y)−4f ( y)−4f (−y)]$ for fixed integers n with $n neq 0, pm 1$ in multi-Banach spaces. 2000 MthetcSubjct Clssification: 39B82, 39B52, 46B99