let Omega be set ; ( Omega = {1,2,3,4} implies ( {1} c= Omega & {2} c= Omega & {3} c= Omega & {4} c= Omega & {1,2} c= Omega & {3,4} c= Omega & {} c= Omega & Omega c= Omega ) )
assume A0:
Omega = {1,2,3,4}
; ( {1} c= Omega & {2} c= Omega & {3} c= Omega & {4} c= Omega & {1,2} c= Omega & {3,4} c= Omega & {} c= Omega & Omega c= Omega )
then
( 1 in Omega & 2 in Omega & 3 in Omega & 4 in Omega )
by ENUMSET1:def 2;
hence
( {1} c= Omega & {2} c= Omega & {3} c= Omega & {4} c= Omega & {1,2} c= Omega & {3,4} c= Omega & {} c= Omega & Omega c= Omega )
by A0, Lemacik2, ZFMISC_1:31; verum