### Atom - `ŒP`

- Powerset

Tags: `miscellaneous` , `math` , `array` , `combinatorics`

##### Arity: monadic

This atom is monadic, which means it takes one argument.

##### Functionality

Powerset (all subsets, including the empty subset, of `z`

in increasing order of length and then lexicographical ordering).

##### Details

The result will be a list of size `2`

containing all subsets (not necessarily contiguous) of ^{len(z)}`z`

. They are first ordered by length and then by lexicographical order, so `3R ŒP`

returns `[[], [1], [2], [3], [1, 2], [1, 3], [2, 3], [1, 2, 3]]`

.