proposition: Lemma commgMR x y z : [~ x, y * z] = [~ x, z] * [~ x, y] * [~ x, y, z].
proof: Proof. by rewrite commgMJ conjg_mulR mulgA. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat fintype) mathcomp(bigop finset binomial fingroup morphism) mathcomp(automorphism quotient gfunctor)