set A = KurExSet ;
( 5 in Int (Cl (Int KurExSet )) & Int KurExSet = ].4,5.[ \/ ].5,+infty .[ ) by Th20, Th27, TOPS_1:def 1, XXREAL_1:235;
hence Int (Cl (Int KurExSet )) <> Int KurExSet by XXREAL_1:205; :: thesis: verum