proposition: Lemma proper_meetsxx T (F : set_system T) (FF : ProperFilter F) : F `#` F.
proof: Proof. by rewrite meetsxx; apply: filter_not_empty. Qed.
imports: HB(structures) mathcomp(all_ssreflect all_algebra finmap generic_quotient) mathcomp(boolp classical_sets functions) mathcomp(cardinality mathcomp_extra fsbigop) reals signed