Study of some functional equations related to some algebras of matrices

Let K be the real or complex field. Let 1 < n < p be two positive integers. We denote Mp(K) the usual algebra of p x p-matrices. Let An be an n- dimensional subalgebra of Mp(K). Then there exists an injective linear mapping A : Kn- Mp(K) such that A^") = An' Therefore K" may be equipped with a product denoted * such that (Kn, +,*) is an associative algebra. The aim of this paper is to investigate the general solutions of the functional equation: f(x*y) = f(x) f(y), and its Pexider form f(x*y) = g(x) h(y), for all x, y in Kn, where f,g, h: Kn - K are unknown functions. This work is inspired by the paper [2].