List.take_left: law of bend-mathlib@0.8.1.0
Import: import bend-mathlib@0.8.1.0/list.bend as List
Lines 1077-1083 of bend-mathlib@0.8.1.0/list.bend: https://jend.leeeet.dev/read.txt?path=bend-mathlib@0.8.1.0/list.bend&start_line=1077&end_line=1083

import Base

# Taking the length of the first part of an append gives the first part back.
law take_left:
  for -a: Quant
  for -A: Kind(a)
  for xs: List<a, A>
  for ys: List<a, A>
  {List.take(a, A, List.append(a, A, xs, ys), List.length(a, A, xs)) == xs : List<a, A>}

Uses (5):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.append
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.length
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=List.take
  https://jend.leeeet.dev/definition.txt?path=bend-mathlib@0.8.1.0/list.bend&name=take_zero