If.u=(a,b,c,d),list.all.possible.subsets.of.u
4 answers
Thanks
Uhm what?
a, ab, ac, ad, abc, abd, acd
b, bc, bd, bcd
c, cd
d
b, bc, bd, bcd
c, cd
d
if not confining yourself to proper subsets, there's also
abcd and the empty set
abcd and the empty set