lean4-htt/tests/lean/run/nestedIssueMatch.lean
2024-03-13 07:56:27 +00:00

20 lines
398 B
Text

def g (t : Nat) : Nat := match t with
| (n+1) => match g n with
| 0 => 0
| m + 1 => match g (n - m) with
| 0 => 0
| m + 1 => g n
| 0 => 0
decreasing_by all_goals sorry
attribute [simp] g
#check g.eq_1
#check g.eq_2
theorem ex3 : g (n + 1) = match g n with
| 0 => 0
| m + 1 => match g (n - m) with
| 0 => 0
| m + 1 => g n := by
conv => lhs; unfold g