law map_id_sym

bend-mathlib@0.8.1.0 · list.bend:2679

import Base

2679# Mapping the identity gives the list back, reversed to rewrite toward the simple side.
2680law map_id_sym:
2681  for ~A: Type
2682  for xs: List<A>
2683  {xs == List.map(~A, ~A, ~(x => x), xs) : List<A>}