def perm

bendlib-kernel-list@1.0.0.0 · list.bend:41

import Base

41# Some swap derivation carries `xs` to `ys` (the existential `perm`).
42def perm(-A: Data, xs: List<&2, A>, ys: List<&2, A>) -> Data:
43  Sigma<&2, &2, List<&2, Nat>, s => perm_steps(A, s, xs, ys)>