lean2/tests/lean/hott/inv_bug.hlean

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open nat
open eq.ops
inductive even : nat → Type :=
| even_zero : even zero
| even_succ_of_odd : ∀ {a}, odd a → even (succ a)
with odd : nat → Type :=
| odd_succ_of_even : ∀ {a}, even a → odd (succ a)
example : even 1 → empty :=
begin
intro He1,
cases He1 with (a, Ho0),
cases Ho0
end
example : even 3 → empty :=
begin
intro He3,
cases He3 with (a, Ho2),
cases Ho2 with (a, He1),
cases He1 with (a, Ho0),
cases Ho0
end