proposition: Lemma fmvalJ u x : x \in 'N(A) -> val (u ^@ x) = val u ^ x.
proof: Proof. by move=> Nx; rewrite fmvalJcond Nx. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq path) mathcomp(div choice fintype bigop ssralg finset fingroup) mathcomp(morphism perm finalg action gproduct commutator) mathcomp(cyclic)