w_s
Selects a subset of the permutation when it is regarded as a list. It is important to note that the output may not be a valid permutation.
The indices should be 0-indexed.
i1 : p = permutation {3,1,2,5,4} o1 = Permutation{3, 1, 2, 5, 4} o1 : Permutation
i2 : p_(1,2) o2 = {1, 2} o2 : List