Theorem: WeierstrassCurve.natDegree_coeff_ΨSq_ofNat
File: Mathlib/AlgebraicGeometry/EllipticCurve/DivisionPolynomial/Degree.lean

tactic: let dp {m n p} : _ → (p ^ n : R[X]).natDegree ≤ n * m := natDegree_pow_le_of_le n
state_before: R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
n : ℕ
⊢ (W.ΨSq ↑n).natDegree ≤ n ^ 2 - 1 ∧ (W.ΨSq ↑n).coeff (n ^ 2 - 1) = ↑(↑n ^ 2)
state_after: R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
n : ℕ
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
⊢ (W.ΨSq ↑n).natDegree ≤ n ^ 2 - 1 ∧ (W.ΨSq ↑n).coeff (n ^ 2 - 1) = ↑(↑n ^ 2)

tactic: let h {n} := W.natDegree_coeff_preΨ' n
state_before: R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
n : ℕ
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
⊢ (W.ΨSq ↑n).natDegree ≤ n ^ 2 - 1 ∧ (W.ΨSq ↑n).coeff (n ^ 2 - 1) = ↑(↑n ^ 2)
state_after: R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
n : ℕ
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
⊢ (W.ΨSq ↑n).natDegree ≤ n ^ 2 - 1 ∧ (W.ΨSq ↑n).coeff (n ^ 2 - 1) = ↑(↑n ^ 2)

tactic: rcases n with _ | n
state_before: R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
n : ℕ
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
⊢ (W.ΨSq ↑n).natDegree ≤ n ^ 2 - 1 ∧ (W.ΨSq ↑n).coeff (n ^ 2 - 1) = ↑(↑n ^ 2)
state_after: case zero
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
⊢ (W.ΨSq ↑0).natDegree ≤ 0 ^ 2 - 1 ∧ (W.ΨSq ↑0).coeff (0 ^ 2 - 1) = ↑(↑0 ^ 2)

case succ
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
⊢ (W.ΨSq ↑(n + 1)).natDegree ≤ (n + 1) ^ 2 - 1 ∧ (W.ΨSq ↑(n + 1)).coeff ((n + 1) ^ 2 - 1) = ↑(↑(n + 1) ^ 2)

tactic: simp
state_before: case zero
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
⊢ (W.ΨSq ↑0).natDegree ≤ 0 ^ 2 - 1 ∧ (W.ΨSq ↑0).coeff (0 ^ 2 - 1) = ↑(↑0 ^ 2)

case succ
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
⊢ (W.ΨSq ↑(n + 1)).natDegree ≤ (n + 1) ^ 2 - 1 ∧ (W.ΨSq ↑(n + 1)).coeff ((n + 1) ^ 2 - 1) = ↑(↑(n + 1) ^ 2)
state_after: case succ
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
⊢ (W.ΨSq ↑(n + 1)).natDegree ≤ (n + 1) ^ 2 - 1 ∧ (W.ΨSq ↑(n + 1)).coeff ((n + 1) ^ 2 - 1) = ↑(↑(n + 1) ^ 2)

tactic: have hd : (n + 1) ^ 2 - 1 = 2 * expDegree (n + 1) + if Even (n + 1) then 3 else 0 := by
  push_cast [← @Nat.cast_inj ℤ, add_sq, expDegree_cast (by omega : n + 1 ≠ 0)]
  split_ifs <;> ring1
state_before: case succ
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
⊢ (W.ΨSq ↑(n + 1)).natDegree ≤ (n + 1) ^ 2 - 1 ∧ (W.ΨSq ↑(n + 1)).coeff ((n + 1) ^ 2 - 1) = ↑(↑(n + 1) ^ 2)
state_after: case succ
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
⊢ (W.ΨSq ↑(n + 1)).natDegree ≤ (n + 1) ^ 2 - 1 ∧ (W.ΨSq ↑(n + 1)).coeff ((n + 1) ^ 2 - 1) = ↑(↑(n + 1) ^ 2)

tactic: have hc : (n + 1) ^ 2 = expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1 := by
  push_cast [← @Int.cast_inj ℚ, expCoeff_cast]
  split_ifs <;> ring1
state_before: case succ
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
⊢ (W.ΨSq ↑(n + 1)).natDegree ≤ (n + 1) ^ 2 - 1 ∧ (W.ΨSq ↑(n + 1)).coeff ((n + 1) ^ 2 - 1) = ↑(↑(n + 1) ^ 2)
state_after: case succ
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ (W.ΨSq ↑(n + 1)).natDegree ≤ (n + 1) ^ 2 - 1 ∧ (W.ΨSq ↑(n + 1)).coeff ((n + 1) ^ 2 - 1) = ↑(↑(n + 1) ^ 2)

tactic: rw [ΨSq_ofNat, hd]
state_before: case succ
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ (W.ΨSq ↑(n + 1)).natDegree ≤ (n + 1) ^ 2 - 1 ∧ (W.ΨSq ↑(n + 1)).coeff ((n + 1) ^ 2 - 1) = ↑(↑(n + 1) ^ 2)
state_after: case succ
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ ((W.preΨ' (n + 1) ^ 2 * if Even (n + 1) then W.Ψ₂Sq else 1).natDegree ≤
      2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0) ∧
    (W.preΨ' (n + 1) ^ 2 * if Even (n + 1) then W.Ψ₂Sq else 1).coeff
        (2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0) =
      ↑(↑(n + 1) ^ 2)

tactic: constructor
state_before: case succ
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ ((W.preΨ' (n + 1) ^ 2 * if Even (n + 1) then W.Ψ₂Sq else 1).natDegree ≤
      2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0) ∧
    (W.preΨ' (n + 1) ^ 2 * if Even (n + 1) then W.Ψ₂Sq else 1).coeff
        (2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0) =
      ↑(↑(n + 1) ^ 2)
state_after: case succ.left
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ (W.preΨ' (n + 1) ^ 2 * if Even (n + 1) then W.Ψ₂Sq else 1).natDegree ≤
    2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0

case succ.right
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ (W.preΨ' (n + 1) ^ 2 * if Even (n + 1) then W.Ψ₂Sq else 1).coeff
      (2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0) =
    ↑(↑(n + 1) ^ 2)

tactic: push_cast [← @Nat.cast_inj ℤ, add_sq, expDegree_cast (by omega : n + 1 ≠ 0)]
state_before: R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
⊢ (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
state_after: R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
⊢ ↑n ^ 2 + 2 * ↑n * 1 = (↑n ^ 2 + 2 * ↑n * 1 + 1 - if Even (n + 1) then 4 else 1) + if Even (n + 1) then 3 else 0

tactic: split_ifs <;> ring1
state_before: R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
⊢ ↑n ^ 2 + 2 * ↑n * 1 = (↑n ^ 2 + 2 * ↑n * 1 + 1 - if Even (n + 1) then 4 else 1) + if Even (n + 1) then 3 else 0
state_after: no goals

tactic: omega
state_before: R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
⊢ n + 1 ≠ 0
state_after: no goals

tactic: push_cast [← @Int.cast_inj ℚ, expCoeff_cast]
state_before: R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
⊢ (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
state_after: R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
⊢ (↑n + 1) ^ 2 = (if Even (n + 1) then (↑n + 1) / 2 else ↑n + 1) ^ 2 * if Even (n + 1) then 4 else 1

tactic: split_ifs <;> ring1
state_before: R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
⊢ (↑n + 1) ^ 2 = (if Even (n + 1) then (↑n + 1) / 2 else ↑n + 1) ^ 2 * if Even (n + 1) then 4 else 1
state_after: no goals

tactic: refine natDegree_mul_le_of_le (dp h.1) ?_
state_before: case succ.left
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ (W.preΨ' (n + 1) ^ 2 * if Even (n + 1) then W.Ψ₂Sq else 1).natDegree ≤
    2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
state_after: case succ.left
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ (if Even (n + 1) then W.Ψ₂Sq else 1).natDegree ≤ if Even (n + 1) then 3 else 0

tactic: split_ifs <;> simp only [apply_ite natDegree, natDegree_one.le, W.natDegree_Ψ₂Sq_le]
state_before: case succ.left
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ (if Even (n + 1) then W.Ψ₂Sq else 1).natDegree ≤ if Even (n + 1) then 3 else 0
state_after: no goals

tactic: erw [coeff_mul_of_natDegree_le (dp h.1), coeff_pow_of_natDegree_le h.1, h.2, apply_ite₂ coeff,
  coeff_Ψ₂Sq, coeff_one_zero, hc]
state_before: case succ.right
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ (W.preΨ' (n + 1) ^ 2 * if Even (n + 1) then W.Ψ₂Sq else 1).coeff
      (2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0) =
    ↑(↑(n + 1) ^ 2)
state_after: case succ.right
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ (↑(WeierstrassCurve.expCoeff (n + 1)) ^ 2 * if Even (n + 1) then 4 else 1) =
    ↑(WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1)

case succ.right
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ (if Even (n + 1) then W.Ψ₂Sq else 1).natDegree ≤ if Even (n + 1) then 3 else 0

tactic: norm_cast
state_before: case succ.right
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ (↑(WeierstrassCurve.expCoeff (n + 1)) ^ 2 * if Even (n + 1) then 4 else 1) =
    ↑(WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1)

case succ.right
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ (if Even (n + 1) then W.Ψ₂Sq else 1).natDegree ≤ if Even (n + 1) then 3 else 0
state_after: case succ.right
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ (if Even (n + 1) then W.Ψ₂Sq else 1).natDegree ≤ if Even (n + 1) then 3 else 0

tactic: split_ifs <;> simp only [apply_ite natDegree, natDegree_one.le, W.natDegree_Ψ₂Sq_le]
state_before: case succ.right
R : Type u
inst✝ : CommRing R
W : WeierstrassCurve R
dp : ∀ {m n : ℕ} {p : R[X]}, p.natDegree ≤ m → (p ^ n).natDegree ≤ n * m := fun {m n} {p} => natDegree_pow_le_of_le n
h : ∀ {n : ℕ},
  (W.preΨ' n).natDegree ≤ WeierstrassCurve.expDegree n ∧
    (W.preΨ' n).coeff (WeierstrassCurve.expDegree n) = ↑(WeierstrassCurve.expCoeff n) :=
  fun {n} => WeierstrassCurve.natDegree_coeff_preΨ' W n
n : ℕ
hd : (n + 1) ^ 2 - 1 = 2 * WeierstrassCurve.expDegree (n + 1) + if Even (n + 1) then 3 else 0
hc : (↑n + 1) ^ 2 = WeierstrassCurve.expCoeff (n + 1) ^ 2 * if Even (n + 1) then 4 else 1
⊢ (if Even (n + 1) then W.Ψ₂Sq else 1).natDegree ≤ if Even (n + 1) then 3 else 0
state_after: no goals