proposition: Lemma closed_closure (A : set T) : closed (closure A).
proof: Proof. by move=> p clclAp B /nbhs_interior /clclAp [q [clAq /clAq]]. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed