set A = KurExSet ;
(Cl KurExSet) ` = ].-infty,1.[ \/ ].1,2.[ by Th10, BORSUK_5:63;
then Cl ((Cl KurExSet) `) = ].-infty,2.] by BORSUK_5:64;
then (Cl ((Cl KurExSet) `)) ` = ].2,+infty.[ by TOPMETR:17, XXREAL_1:224, XXREAL_1:288;
hence Int (Cl KurExSet) = ].2,+infty.[ by TOPS_1:def 1; :: thesis: verum