intro v
n : ℕ
i j : Fin n
F : Vector ℕ (n + 1) → ℕ := fun v => (v.get j.succ).isDvdNat (v.get i.succ - v.head)
this : Arith₁ F
⊢ ∀ (i_1 : Vector ℕ n), (rfind fun n_1 => Part.some (decide (0 < F (n_1 ::ᵥ i_1)))) = (↑fun v => v.get i % v.get j) i_1
n : ℕ
i j : Fin n
F : Vector ℕ (n + 1) → ℕ := fun v => (v.get j.succ).isDvdNat (v.get i.succ - v.head)
this : Arith₁ F
v : Vector ℕ n
⊢ (rfind fun n_1 => Part.some (decide (0 < F (n_1 ::ᵥ v)))) = (↑fun v => v.get i % v.get j) v