Theorem: LO.FirstOrder.Arith.Model.under_succ (Arithmetization/ISigmaOne/Bit.lean)

State before:
M : Type u_1
inst✝⁵ : Zero M
inst✝⁴ : One M
inst✝³ : Add M
inst✝² : Mul M
inst✝¹ : LT M
inst✝ : M ⊧ₘ* 𝐈𝚺₁
i : M
⊢ ∀ (i_1 : M), i_1 ∈ under (i + 1) ↔ i_1 ∈ insert i (under i)
Tactic:
simp [mem_under_iff, lt_succ_iff_le, le_iff_eq_or_lt]
State after:
no goals