law sub_sub_sym

bend-mathlib@0.8.1.0 · nat.bend:4055

import Base

4055# Subtracting twice is subtracting the sum: (n - m) - k = n - (m + k), reversed to rewrite toward the simple side.
4056law sub_sub_sym:
4057  for n: Nat
4058  for m: Nat
4059  for k: Nat
4060  {Nat.sub(n, Nat.add(m, k)) == Nat.sub(Nat.sub(n, m), k) : Nat}