w_n
Selects an element from the permutation when it is regarded as a list. The index should be 1-indexed.
Given a permutation $p$ and index $i$, this is the same as $p(i)$.
i1 : p = permutation {3,1,2,5,4} o1 = Permutation{3, 1, 2, 5, 4} o1 : Permutation
i2 : p_1 o2 = 3