PROOF.un.sub_add_l: def of bend-osdev-u32@0.1.0.0
Import: import bend-osdev-u32@0.1.0.0/PROOF.bend as PROOF
Lines 90-99 of bend-osdev-u32@0.1.0.0/PROOF.bend: https://jend.leeeet.dev/read.txt?path=bend-osdev-u32@0.1.0.0/PROOF.bend&start_line=90&end_line=99

import Base

def un.sub_add_l(y: Nat, +r: Nat) -> {Nat.sub(Nat.add(y, r), y) == r : Nat}:
  match y:
    case 0n:
      match r:
        case 0n:
          {==}
        case 1n+q:
          {==}
    case 1n+q:
      un.sub_add_l(q, r)

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=Base/base.bend&name=Nat.sub