Antimirov and Mosses presented a rewrite system for deciding the equivalence of two (extended) regular expressions and argued that this method could lead to a better average-case algorithm than those based on the comparison of the equivalent minimal \dfas. In this paper we present a functional approach of a variant of that method, prove its correctness and give some experimental comparative results. Although being a refutation method, our preliminary results lead to the conclusion that indeed this method is feasible and it is, almost always, faster than the classical methods.