Recent results on the stability of the parametric fundamental equation of information

The purpose of this paper is to summarize the recent results on the stability of the parametric fundamental equation of information. Furthermore, by the help of a modification of a method we used in \cite{GM08} we shall give a unified proof for the Hyers--Ulam stability of the equation in question, assuming that the parameter does not equal to 1. As a corollary of the main result, a system of equations, that defines the recursive and semi--symmetric information measures is also discussed.