Theorem: N.zero_add' (LeanTeaching/TD/TD02_sol.lean)

State before:
S : Type
image_zero : S
image_succ : N → S → S
n m a b c : N
⊢ zero + a = a
Tactic:
induction a with
| zero =>
  rw [add_zero']
| succ n hn =>
  rw [add_succ, hn]
State after:
no goals

State before:
case zero
S : Type
image_zero : S
image_succ : N → S → S
n m a b c : N
⊢ zero + zero = zero
Tactic:
rw [add_zero']
State after:
no goals

State before:
case succ
S : Type
image_zero : S
image_succ : N → S → S
n✝ m a b c n : N
hn : zero + n = n
⊢ zero + succ n = succ n
Tactic:
rw [add_succ, hn]
State after:
no goals