proposition: Lemma setring_id : setring G -> <<r G >> = G.
proof: Proof. by move=> /smallest_id->. Qed.
imports: mathcomp(all_ssreflect all_algebra finmap) mathcomp(mathcomp_extra boolp classical_sets functions) mathcomp(cardinality fsbigop ) reals ereal signed topology normedtype sequences esum numfun HB(structures)