proposition: Lemma mulg1 : right_id 1 mulgT.
proof: Proof. by move=> x; apply: invg_inj; rewrite invMg invg1 mul1g. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype div path tuple bigop prime finset)