law any_map

bend-mathlib@0.8.1.0 · list.bend:1522

import Base

1522# Any over a map checks the composed predicate: any p (map f xs) = any (p . f) xs.
1523law any_map:
1524  for ~A: Type
1525  for ~B: Type
1526  for ~f: A -> B
1527  for ~p: B -> Bool
1528  for xs: List<A>
1529  {List.any(~&1, ~B, ~p, List.map(~A, ~B, ~f, xs)) == List.any(~&1, ~A, ~(x => p(f(x))), xs) : Bool}