ŒP - Powerset
Tags: miscellaneous , math , array , combinatorics
This atom is monadic, which means it takes one argument.
Powerset (all subsets, including the empty subset, of
z in increasing order of length and then lexicographical ordering).
The result will be a list of size
2len(z) containing all subsets (not necessarily contiguous) of
z. They are first ordered by length and then by lexicographical order, so
3R ŒP returns
[, , , , [1, 2], [1, 3], [2, 3], [1, 2, 3]].