proposition: Lemma mem_repr_rcoset x : repr (G :* x) \in G :* x.
proof: Proof. exact: mem_repr (rcoset_refl x). Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype div path tuple bigop prime finset)