proposition: Lemma closure_subset A B : A `<=` B -> closure A `<=` closure B.
proof: Proof. by move=> ? ? CAx ?; move/CAx; exact/subsetI_neq0. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed