Permutation from SubexcedantSeq
The permutation a subexcedant sequence is the inversion sequence of.
Declines a word that isn't subexcedant: entry i must lie in 0..i − 1.
Called as CombinatorialMap(x, "Permutation"). The head's page has its examples.
Also from
The same name out of other carriers, each its own implementation: CycleDecomposition.