proposition: Lemma entourage_refl (A : set (M * M)) x : entourage A -> A (x, x).
proof: Proof. by move=> entA; apply: entourage_refl_subproof entA _ _. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed