:: deftheorem Def4 defines { ENUMSET1:def 4 :
for x1, x2, x3, x4, x5, x6 being object
for b₇ being set holds
( b₇ = {x1,x2,x3,x4,x5,x6} iff for x being object holds
( x in b₇ iff ( x = x1 or x = x2 or x = x3 or x = x4 or x = x5 or x = x6 ) ) );