law add_add_add_comm

bend-mathlib@0.8.1.0 · nat.bend:118

import Base

118# Four-way regrouping of a sum: (a + b) + (c + d) = (a + c) + (b + d).
119law add_add_add_comm:
120  for a: Nat
121  for b: Nat
122  for c: Nat
123  for -d: Nat
124  {Nat.add(Nat.add(a, b), Nat.add(c, d)) == Nat.add(Nat.add(a, c), Nat.add(b, d)) : Nat}