proposition: Lemma lcoset_inj : right_injective (fun x A => x *: A).
proof: Proof. by move=> x; apply: can_inj (lcosetK x). Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype div path tuple bigop prime finset)