ProofTree.lo_fst: law of lawful-arrays@0.1.0.0
Import: import lawful-arrays@0.1.0.0/proof_tree.bend as ProofTree
Lines 58-62 of lawful-arrays@0.1.0.0/proof_tree.bend: https://jend.leeeet.dev/read.txt?path=lawful-arrays@0.1.0.0/proof_tree.bend&start_line=58&end_line=62

import Base

law lo_fst:
  for -T: Type
  for -ys: Array<T>
  for r: Array<T> & T
  {Pair.fst(Array<T>, T, Array.swap.lo(T, ys, r)) == ANode{Pair.fst(Array<T>, T, r), ys} : Array<T>}

Uses (5):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Array
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Array.swap.lo
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Pair
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Pair.fst
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Sigma