set A = KurExSet ;
A1: 2 in Cl (Int (Cl KurExSet )) by Th29, XXREAL_1:236;
Int KurExSet = ].4,5.[ \/ ].5,+infty .[ by Th20, TOPS_1:def 1;
hence Cl (Int (Cl KurExSet )) <> Int KurExSet by A1, XXREAL_1:223; :: thesis: verum