set A = KurExSet ;
A1: 5 in Int (Cl (Int KurExSet )) by Th27, XXREAL_1:235;
Int KurExSet = ].4,5.[ \/ ].5,+infty .[ by Th20, TOPS_1:def 1;
hence Int (Cl (Int KurExSet )) <> Int KurExSet by A1, XXREAL_1:205; :: thesis: verum