proposition: Lemma clopen0 {T} : @clopen T set0.
proof: Proof. by split; [exact: open0 | exact: closed0]. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed