exact le_mul_self_of_pos_right
  (pos_iff_ne_zero.mpr (show c ≠ 0 from by rintro rfl; simp at h))
case intro
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* 𝐏𝐀⁻
a c✝ c : M
h : 0 < a * c
⊢ a ≤ a * c
no goals