A1:
omega +` omega = omega
by CARD_3:117;
( INT c= NAT \/ [:{0 },NAT :] & card [:NAT ,{0 }:] = card NAT & card [:NAT ,{0 }:] = card [:{0 },NAT :] )
by CARD_2:11, CARD_2:13, NUMBERS:def 4;
then
( card INT c= card (NAT \/ [:{0 },NAT :]) & card (NAT \/ [:{0 },NAT :]) c= omega )
by A1, CARD_1:27, CARD_1:84, CARD_2:47;
hence
card INT c= omega
by XBOOLE_1:1; :: according to XBOOLE_0:def 10 :: thesis: omega c= card INT
thus
omega c= card INT
by CARD_1:27, CARD_1:84, NUMBERS:17; :: thesis: verum