proposition: Lemma rcosetKV : rev_right_loop invg (fun A x => A :* x).
proof: Proof. by move=> x A; rewrite -rcosetM mulVg mulg1. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype div path tuple bigop prime finset)