dom <%x,y,z%> = {0,1,2} by AFINSQ_1:39, CARD_1:51;
then ( 0 in dom <%x,y,z%> & 1 in dom <%x,y,z%> ) by ENUMSET1:def 1;
hence not <%x,y,z%> is trivial by ZFMISC_1:def 10; :: thesis: verum