ProofNat.add_cancel_l: law of lawful-words@0.1.0.0
Import: import lawful-words@0.1.0.0/proof_nat.bend as ProofNat
Lines 274-280 of lawful-words@0.1.0.0/proof_nat.bend: https://jend.leeeet.dev/read.txt?path=lawful-words@0.1.0.0/proof_nat.bend&start_line=274&end_line=280

import Base

# a + x = a + y gives x = y.
law add_cancel_l:
  for +a: Nat
  for +x: Nat
  for +y: Nat
  for e: {Nat.add(a, x) == Nat.add(a, y) : Nat}
  {x == y : Nat}

Uses (3):
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat
  https://jend.leeeet.dev/definition.txt?path=Base/base.bend&name=Nat.add
  https://jend.leeeet.dev/definition.txt?path=lawful-words@0.1.0.0/proof_nat.bend&name=succ_inj