theorem Th10:
for
X being
set for
a1,
a2,
a3,
a4,
a5,
a6,
a7,
a8,
a9,
a10 being
object st
a1 in X &
a2 in X &
a3 in X &
a4 in X &
a5 in X &
a6 in X &
a7 in X &
a8 in X &
a9 in X &
a10 in X holds
{a1,a2,a3,a4,a5,a6,a7,a8,a9,a10} c= X by ENUMSET1:def 8;