set A = KurExSet ;
( 5 in Int (Cl KurExSet) & Int KurExSet = ].4,5.[ \/ ].5,+infty.[ ) by Th18, Th26, TOPS_1:def 1, XXREAL_1:235;
hence Int (Cl KurExSet) <> Int KurExSet by XXREAL_1:205; :: thesis: verum