case intro
M : Type u_1
inst✝ : CancelCommMonoidWithZero M
q : Associates M
n : ℕ
c : Fin (n + 1) → Associates M
h₁ : StrictMono c
h₂ : ∀ {r : Associates M}, r ≤ q ↔ ∃ i, r = c i
i : Fin (n + 1)
hr : 1 = c i
⊢ IsUnit (c 0)
M : Type u_1
inst✝ : CancelCommMonoidWithZero M
q : Associates M
n : ℕ
c : Fin (n + 1) → Associates M
h₁ : StrictMono c
h₂ : ∀ {r : Associates M}, r ≤ q ↔ ∃ i, r = c i
⊢ IsUnit (c 0)
obtain ⟨i, hr⟩ := h₂.mp Associates.one_le
case intro
M : Type u_1
inst✝ : CancelCommMonoidWithZero M
q : Associates M
n : ℕ
c : Fin (n + 1) → Associates M
h₁ : StrictMono c
h₂ : ∀ {r : Associates M}, r ≤ q ↔ ∃ i, r = c i
i : Fin (n + 1)
hr : 1 = c i
⊢ c 0 ≤ c i
case intro
M : Type u_1
inst✝ : CancelCommMonoidWithZero M
q : Associates M
n : ℕ
c : Fin (n + 1) → Associates M
h₁ : StrictMono c
h₂ : ∀ {r : Associates M}, r ≤ q ↔ ∃ i, r = c i
i : Fin (n + 1)
hr : 1 = c i
⊢ IsUnit (c 0)
rw [Associates.isUnit_iff_eq_one, ← Associates.le_one_iff, hr]
no goals
case intro
M : Type u_1
inst✝ : CancelCommMonoidWithZero M
q : Associates M
n : ℕ
c : Fin (n + 1) → Associates M
h₁ : StrictMono c
h₂ : ∀ {r : Associates M}, r ≤ q ↔ ∃ i, r = c i
i : Fin (n + 1)
hr : 1 = c i
⊢ c 0 ≤ c i
exact h₁.monotone (Fin.zero_le i)