set A = KurExSet ;
( 4 in Cl (Int KurExSet) & Int KurExSet = ].4,5.[ \/ ].5,+infty.[ ) by Th18, Th24, TOPS_1:def 1, XXREAL_1:236;
hence Cl (Int KurExSet) <> Int KurExSet by XXREAL_1:223; :: thesis: verum