rcases le_one_iff_eq_zero_or_one.mp leu with (rfl | rfl) <;> simp
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* 𝐈𝚫₀
u : M
leu : u ≤ 1
⊢ u ≠ 2 → PPow2 u → Seqₛ.Even seqX₀ seqY₀ u ∨ Seqₛ.Odd seqX₀ seqY₀ u
no goals