Maybe.maybe_is_none_map_sym: law of bend-mathlib@0.8.1.0
Import: import bend-mathlib@0.8.1.0/maybe.bend as Maybe
Lines 323-329 of bend-mathlib@0.8.1.0/maybe.bend: https://jend.leeeet.dev/read.txt?path=bend-mathlib@0.8.1.0/maybe.bend&start_line=323&end_line=329

import Base

# Mapping keeps whether a value is absent, reversed to rewrite toward the simple side.
law maybe_is_none_map_sym:
  for ~A: Data
  for ~B: Data
  for ~f: A -> B
  for m: Maybe<&2, A>
  {Maybe.is_none(&2, A, m) == Maybe.is_none(&2, B, Maybe.map(&2, A, B, f, m)) : Bool}

Uses (6):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Bool
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Equal.sym
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe.is_none
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Maybe.map
  https://jend.leeeet.dev/definition.txt?path=bend-mathlib@0.8.1.0/maybe.bend&name=maybe_is_none_map