proposition: Lemma memV_lcosetV x y : (y^-1 \in x^-1 *: G) = (y \in G :* x).
proof: Proof. by rewrite -invg_rcoset memV_invg. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype div path tuple bigop prime finset)