STABILITY OF FUNCTIONAL EQUATIONS IN NON-ARCHIMEDEAN SPACES

We prove the generalized HYERS-ULAM stability of the CAUCHY functional equation f(x + y) = f (x)+ f (y) and the quadratic functional equation f (x + y) + f (x - y) = 2f(x) + 2f(y) in non-Archimedean normed spaces.