proposition: Lemma fct_ent_refl A : fct_ent A -> [set fg | fg.1 = fg.2] `<=` A.
proof: Proof. move=> [B entB sBA] fg feg; apply/sBA => t; rewrite feg. exact: entourage_refl. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed