l3lab/ntp-mathlib huggingface dataset:
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  

Proof state:
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
⊢ Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1

Next tactic:
by_contra H
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  

Proof state:
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
⊢ False

Next tactic:
obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  

Proof state:
case intro.intro.intro
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : p ∣ Int.natAbs (m ^ 2 - n ^ 2)
hp2 : p ∣ Int.natAbs (2 * m * n)
⊢ False

Next tactic:
rw [← Int.coe_nat_dvd_left] at hp1 hp2
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  

Proof state:
case intro.intro.intro
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2 : ↑p ∣ 2 * m * n
⊢ False

Next tactic:
have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    

Proof state:
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2 : ↑p ∣ 2 * m * n
⊢ ¬↑p ∣ ↑(Int.gcd m n)

Next tactic:
rw [h]
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    

Proof state:
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2 : ↑p ∣ 2 * m * n
⊢ ¬↑p ∣ ↑1

Next tactic:
norm_cast
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    

Proof state:
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2 : ↑p ∣ 2 * m * n
⊢ ¬p ∣ 1

Next tactic:
exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  

Proof state:
case intro.intro.intro
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2 : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
⊢ False

Next tactic:
cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · 

Proof state:
case intro.intro.intro.inl
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2 : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
hp2m : p ∣ Int.natAbs (2 * m)
⊢ False

Next tactic:
rw [Int.natAbs_mul] at hp2m
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · rw [Int.natAbs_mul] at hp2m
    

Proof state:
case intro.intro.intro.inl
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2 : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
hp2m : p ∣ Int.natAbs 2 * Int.natAbs m
⊢ False

Next tactic:
cases' (Nat.Prime.dvd_mul hp).mp hp2m with hp2 hpm
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · rw [Int.natAbs_mul] at hp2m
    cases' (Nat.Prime.dvd_mul hp).mp hp2m with hp2 hpm
    · 

Proof state:
case intro.intro.intro.inl.inl
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2✝ : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
hp2m : p ∣ Int.natAbs 2 * Int.natAbs m
hp2 : p ∣ Int.natAbs 2
⊢ False

Next tactic:
have hp2' : p = 2 := (Nat.le_of_dvd zero_lt_two hp2).antisymm hp.two_le
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · rw [Int.natAbs_mul] at hp2m
    cases' (Nat.Prime.dvd_mul hp).mp hp2m with hp2 hpm
    · have hp2' : p = 2 := (Nat.le_of_dvd zero_lt_two hp2).antisymm hp.two_le
      

Proof state:
case intro.intro.intro.inl.inl
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2✝ : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
hp2m : p ∣ Int.natAbs 2 * Int.natAbs m
hp2 : p ∣ Int.natAbs 2
hp2' : p = 2
⊢ False

Next tactic:
revert hp1
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · rw [Int.natAbs_mul] at hp2m
    cases' (Nat.Prime.dvd_mul hp).mp hp2m with hp2 hpm
    · have hp2' : p = 2 := (Nat.le_of_dvd zero_lt_two hp2).antisymm hp.two_le
      revert hp1
      

Proof state:
case intro.intro.intro.inl.inl
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp2✝ : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
hp2m : p ∣ Int.natAbs 2 * Int.natAbs m
hp2 : p ∣ Int.natAbs 2
hp2' : p = 2
⊢ ↑p ∣ m ^ 2 - n ^ 2 → False

Next tactic:
rw [hp2']
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · rw [Int.natAbs_mul] at hp2m
    cases' (Nat.Prime.dvd_mul hp).mp hp2m with hp2 hpm
    · have hp2' : p = 2 := (Nat.le_of_dvd zero_lt_two hp2).antisymm hp.two_le
      revert hp1
      rw [hp2']
      

Proof state:
case intro.intro.intro.inl.inl
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp2✝ : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
hp2m : p ∣ Int.natAbs 2 * Int.natAbs m
hp2 : p ∣ Int.natAbs 2
hp2' : p = 2
⊢ ↑2 ∣ m ^ 2 - n ^ 2 → False

Next tactic:
apply mt Int.emod_eq_zero_of_dvd
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · rw [Int.natAbs_mul] at hp2m
    cases' (Nat.Prime.dvd_mul hp).mp hp2m with hp2 hpm
    · have hp2' : p = 2 := (Nat.le_of_dvd zero_lt_two hp2).antisymm hp.two_le
      revert hp1
      rw [hp2']
      apply mt Int.emod_eq_zero_of_dvd
      -- Porting note: norm_num is not enough to close this
      

Proof state:
case intro.intro.intro.inl.inl
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp2✝ : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
hp2m : p ∣ Int.natAbs 2 * Int.natAbs m
hp2 : p ∣ Int.natAbs 2
hp2' : p = 2
⊢ ¬(m ^ 2 - n ^ 2) % ↑2 = 0

Next tactic:
simp only [sq, Nat.cast_ofNat, Int.sub_emod, Int.mul_emod, hm, hn,
        mul_zero, EuclideanDomain.zero_mod, mul_one, zero_sub]
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · rw [Int.natAbs_mul] at hp2m
    cases' (Nat.Prime.dvd_mul hp).mp hp2m with hp2 hpm
    · have hp2' : p = 2 := (Nat.le_of_dvd zero_lt_two hp2).antisymm hp.two_le
      revert hp1
      rw [hp2']
      apply mt Int.emod_eq_zero_of_dvd
      -- Porting note: norm_num is not enough to close this
      simp only [sq, Nat.cast_ofNat, Int.sub_emod, Int.mul_emod, hm, hn,
        mul_zero, EuclideanDomain.zero_mod, mul_one, zero_sub]
      

Proof state:
case intro.intro.intro.inl.inl
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp2✝ : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
hp2m : p ∣ Int.natAbs 2 * Int.natAbs m
hp2 : p ∣ Int.natAbs 2
hp2' : p = 2
⊢ ¬-(1 % 2) % 2 = 0

Next tactic:
decide
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · rw [Int.natAbs_mul] at hp2m
    cases' (Nat.Prime.dvd_mul hp).mp hp2m with hp2 hpm
    · have hp2' : p = 2 := (Nat.le_of_dvd zero_lt_two hp2).antisymm hp.two_le
      revert hp1
      rw [hp2']
      apply mt Int.emod_eq_zero_of_dvd
      -- Porting note: norm_num is not enough to close this
      simp only [sq, Nat.cast_ofNat, Int.sub_emod, Int.mul_emod, hm, hn,
        mul_zero, EuclideanDomain.zero_mod, mul_one, zero_sub]
      decide
    

Proof state:
case intro.intro.intro.inl.inr
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2 : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
hp2m : p ∣ Int.natAbs 2 * Int.natAbs m
hpm : p ∣ Int.natAbs m
⊢ False

Next tactic:
apply mt (Int.dvd_gcd (Int.coe_nat_dvd_left.mpr hpm)) hnp
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · rw [Int.natAbs_mul] at hp2m
    cases' (Nat.Prime.dvd_mul hp).mp hp2m with hp2 hpm
    · have hp2' : p = 2 := (Nat.le_of_dvd zero_lt_two hp2).antisymm hp.two_le
      revert hp1
      rw [hp2']
      apply mt Int.emod_eq_zero_of_dvd
      -- Porting note: norm_num is not enough to close this
      simp only [sq, Nat.cast_ofNat, Int.sub_emod, Int.mul_emod, hm, hn,
        mul_zero, EuclideanDomain.zero_mod, mul_one, zero_sub]
      decide
    apply mt (Int.dvd_gcd (Int.coe_nat_dvd_left.mpr hpm)) hnp
    

Proof state:
case intro.intro.intro.inl.inr
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2 : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
hp2m : p ∣ Int.natAbs 2 * Int.natAbs m
hpm : p ∣ Int.natAbs m
⊢ ↑p ∣ n

Next tactic:
apply or_self_iff.mp
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · rw [Int.natAbs_mul] at hp2m
    cases' (Nat.Prime.dvd_mul hp).mp hp2m with hp2 hpm
    · have hp2' : p = 2 := (Nat.le_of_dvd zero_lt_two hp2).antisymm hp.two_le
      revert hp1
      rw [hp2']
      apply mt Int.emod_eq_zero_of_dvd
      -- Porting note: norm_num is not enough to close this
      simp only [sq, Nat.cast_ofNat, Int.sub_emod, Int.mul_emod, hm, hn,
        mul_zero, EuclideanDomain.zero_mod, mul_one, zero_sub]
      decide
    apply mt (Int.dvd_gcd (Int.coe_nat_dvd_left.mpr hpm)) hnp
    apply or_self_iff.mp
    

Proof state:
case intro.intro.intro.inl.inr
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2 : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
hp2m : p ∣ Int.natAbs 2 * Int.natAbs m
hpm : p ∣ Int.natAbs m
⊢ ↑p ∣ n ∨ ↑p ∣ n

Next tactic:
apply Int.Prime.dvd_mul' hp
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · rw [Int.natAbs_mul] at hp2m
    cases' (Nat.Prime.dvd_mul hp).mp hp2m with hp2 hpm
    · have hp2' : p = 2 := (Nat.le_of_dvd zero_lt_two hp2).antisymm hp.two_le
      revert hp1
      rw [hp2']
      apply mt Int.emod_eq_zero_of_dvd
      -- Porting note: norm_num is not enough to close this
      simp only [sq, Nat.cast_ofNat, Int.sub_emod, Int.mul_emod, hm, hn,
        mul_zero, EuclideanDomain.zero_mod, mul_one, zero_sub]
      decide
    apply mt (Int.dvd_gcd (Int.coe_nat_dvd_left.mpr hpm)) hnp
    apply or_self_iff.mp
    apply Int.Prime.dvd_mul' hp
    

Proof state:
case intro.intro.intro.inl.inr
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2 : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
hp2m : p ∣ Int.natAbs 2 * Int.natAbs m
hpm : p ∣ Int.natAbs m
⊢ ↑p ∣ n * n

Next tactic:
rw [(by ring : n * n = -(m ^ 2 - n ^ 2) + m * m)]
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · rw [Int.natAbs_mul] at hp2m
    cases' (Nat.Prime.dvd_mul hp).mp hp2m with hp2 hpm
    · have hp2' : p = 2 := (Nat.le_of_dvd zero_lt_two hp2).antisymm hp.two_le
      revert hp1
      rw [hp2']
      apply mt Int.emod_eq_zero_of_dvd
      -- Porting note: norm_num is not enough to close this
      simp only [sq, Nat.cast_ofNat, Int.sub_emod, Int.mul_emod, hm, hn,
        mul_zero, EuclideanDomain.zero_mod, mul_one, zero_sub]
      decide
    apply mt (Int.dvd_gcd (Int.coe_nat_dvd_left.mpr hpm)) hnp
    apply or_self_iff.mp
    apply Int.Prime.dvd_mul' hp
    rw [(by 

Proof state:
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2 : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
hp2m : p ∣ Int.natAbs 2 * Int.natAbs m
hpm : p ∣ Int.natAbs m
⊢ n * n = -(m ^ 2 - n ^ 2) + m * m

Next tactic:
ring
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · rw [Int.natAbs_mul] at hp2m
    cases' (Nat.Prime.dvd_mul hp).mp hp2m with hp2 hpm
    · have hp2' : p = 2 := (Nat.le_of_dvd zero_lt_two hp2).antisymm hp.two_le
      revert hp1
      rw [hp2']
      apply mt Int.emod_eq_zero_of_dvd
      -- Porting note: norm_num is not enough to close this
      simp only [sq, Nat.cast_ofNat, Int.sub_emod, Int.mul_emod, hm, hn,
        mul_zero, EuclideanDomain.zero_mod, mul_one, zero_sub]
      decide
    apply mt (Int.dvd_gcd (Int.coe_nat_dvd_left.mpr hpm)) hnp
    apply or_self_iff.mp
    apply Int.Prime.dvd_mul' hp
    rw [(by ring : n * n = -(m ^ 2 - n ^ 2) + m * m)]
    

Proof state:
case intro.intro.intro.inl.inr
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2 : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
hp2m : p ∣ Int.natAbs 2 * Int.natAbs m
hpm : p ∣ Int.natAbs m
⊢ ↑p ∣ -(m ^ 2 - n ^ 2) + m * m

Next tactic:
exact hp1.neg_right.add ((Int.coe_nat_dvd_left.2 hpm).mul_right _)
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · rw [Int.natAbs_mul] at hp2m
    cases' (Nat.Prime.dvd_mul hp).mp hp2m with hp2 hpm
    · have hp2' : p = 2 := (Nat.le_of_dvd zero_lt_two hp2).antisymm hp.two_le
      revert hp1
      rw [hp2']
      apply mt Int.emod_eq_zero_of_dvd
      -- Porting note: norm_num is not enough to close this
      simp only [sq, Nat.cast_ofNat, Int.sub_emod, Int.mul_emod, hm, hn,
        mul_zero, EuclideanDomain.zero_mod, mul_one, zero_sub]
      decide
    apply mt (Int.dvd_gcd (Int.coe_nat_dvd_left.mpr hpm)) hnp
    apply or_self_iff.mp
    apply Int.Prime.dvd_mul' hp
    rw [(by ring : n * n = -(m ^ 2 - n ^ 2) + m * m)]
    exact hp1.neg_right.add ((Int.coe_nat_dvd_left.2 hpm).mul_right _)
  

Proof state:
case intro.intro.intro.inr
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2 : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd m n)
hpn : p ∣ Int.natAbs n
⊢ False

Next tactic:
rw [Int.gcd_comm] at hnp
private theorem coprime_sq_sub_mul_of_even_odd {m n : ℤ} (h : Int.gcd m n = 1) (hm : m % 2 = 0)
    (hn : n % 2 = 1) : Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1 := by
  by_contra H
  obtain ⟨p, hp, hp1, hp2⟩ := Nat.Prime.not_coprime_iff_dvd.mp H
  rw [← Int.coe_nat_dvd_left] at hp1 hp2
  have hnp : ¬(p : ℤ) ∣ Int.gcd m n := by
    rw [h]
    norm_cast
    exact mt Nat.dvd_one.mp (Nat.Prime.ne_one hp)
  cases' Int.Prime.dvd_mul hp hp2 with hp2m hpn
  · rw [Int.natAbs_mul] at hp2m
    cases' (Nat.Prime.dvd_mul hp).mp hp2m with hp2 hpm
    · have hp2' : p = 2 := (Nat.le_of_dvd zero_lt_two hp2).antisymm hp.two_le
      revert hp1
      rw [hp2']
      apply mt Int.emod_eq_zero_of_dvd
      -- Porting note: norm_num is not enough to close this
      simp only [sq, Nat.cast_ofNat, Int.sub_emod, Int.mul_emod, hm, hn,
        mul_zero, EuclideanDomain.zero_mod, mul_one, zero_sub]
      decide
    apply mt (Int.dvd_gcd (Int.coe_nat_dvd_left.mpr hpm)) hnp
    apply or_self_iff.mp
    apply Int.Prime.dvd_mul' hp
    rw [(by ring : n * n = -(m ^ 2 - n ^ 2) + m * m)]
    exact hp1.neg_right.add ((Int.coe_nat_dvd_left.2 hpm).mul_right _)
  rw [Int.gcd_comm] at hnp
  

Proof state:
case intro.intro.intro.inr
m n : ℤ
h : Int.gcd m n = 1
hm : m % 2 = 0
hn : n % 2 = 1
H : ¬Int.gcd (m ^ 2 - n ^ 2) (2 * m * n) = 1
p : ℕ
hp : Nat.Prime p
hp1 : ↑p ∣ m ^ 2 - n ^ 2
hp2 : ↑p ∣ 2 * m * n
hnp : ¬↑p ∣ ↑(Int.gcd n m)
hpn : p ∣ Int.natAbs n
⊢ False

Next tactic:
apply mt (Int.dvd_gcd (Int.coe_nat_dvd_left.mpr hpn)) hnp