simpa using get?_eq_some.mp hm
α : Type u
inst✝¹ : DecidableEq α
β : Type v
inst✝ : DecidableEq β
n : ℕ
f : ℕ → α
m : ℕ
ih : take m (map f (range n)) = map f (range (min n m))
i : ℕ
hm : (range n).get? m = some i
⊢ m < n ∧ m = i
no goals