l3lab/ntp-mathlib huggingface dataset:
theorem gcd_props :
    let d := gcdD a b
    let w := gcdW a b
    let x := gcdX a b
    let y := gcdY a b
    let z := gcdZ a b
    let a' := gcdA' a b
    let b' := gcdB' a b
    w * z = succPNat (x * y) ∧
      a = a' * d ∧
        b = b' * d ∧
          z * a' = succPNat (x * b') ∧
            w * b' = succPNat (y * a') ∧ (z * a : ℕ) = x * b + d ∧ (w * b : ℕ) = y * a + d := by
  intros d w x y z a' b'
  let u := XgcdType.start a b
  let ur := u.reduce

  have _ : d = ur.a := rfl
  have hb : d = ur.b := u.reduce_isReduced'
  have ha' : (a' : ℕ) = w + x := gcdA'_coe a b
  have hb' : (b' : ℕ) = y + z := gcdB'_coe a b
  have hdet : w * z = succPNat (x * y) := u.reduce_isSpecial' rfl
  constructor
  exact hdet
  have hdet' : (w * z : ℕ) = x * y + 1 := by rw [← mul_coe, hdet, succPNat_coe]
  have _ : u.v = ⟨a, b⟩ := XgcdType.start_v a b
  let hv : Prod.mk (w * d + x * ur.b : ℕ) (y * d + z * ur.b : ℕ) = ⟨a, b⟩ :=
    u.reduce_v.trans (XgcdType.start_v a b)
  rw [← hb, ← add_mul, ← add_mul, ← ha', ← hb'] at hv
  have ha'' : (a : ℕ) = a' * d := (congr_arg Prod.fst hv).symm
  have hb'' : (b : ℕ) = b' * d := (congr_arg Prod.snd hv).symm
  constructor
  exact eq ha''
  constructor
  exact eq hb''
  have hza' : (z * a' : ℕ) = x * b' + 1 := by
    rw [ha', hb', mul_add, mul_add, mul_comm (z : ℕ), hdet']
    ring
  have hwb' : (w * b' : ℕ) = y * a' + 1 := by
    rw [ha', hb', mul_add, mul_add, hdet']
    ring
  constructor
  · apply eq
    

Proof state:
case right.right.right.left.a
a b : ℕ+
d : ℕ+ := gcdD a b
w : ℕ+ := gcdW a b
x : ℕ := gcdX a b
y : ℕ := gcdY a b
z : ℕ+ := gcdZ a b
a' : ℕ+ := gcdA' a b
b' : ℕ+ := gcdB' a b
u : XgcdType := XgcdType.start a b
ur : XgcdType := XgcdType.reduce u
x✝¹ : d = XgcdType.a ur
hb : d = XgcdType.b ur
ha' : ↑a' = ↑w + x
hb' : ↑b' = y + ↑z
hdet : w * z = succPNat (x * y)
hdet' : ↑w * ↑z = x * y + 1
x✝ : XgcdType.v u = (↑a, ↑b)
hv : (↑a' * ↑d, ↑b' * ↑d) = (↑a, ↑b)
ha'' : ↑a = ↑a' * ↑d
hb'' : ↑b = ↑b' * ↑d
hza' : ↑z * ↑a' = x * ↑b' + 1
hwb' : ↑w * ↑b' = y * ↑a' + 1
⊢ ↑(z * a') = ↑(succPNat (x * ↑b'))

Next tactic:
rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hza']
theorem gcd_props :
    let d := gcdD a b
    let w := gcdW a b
    let x := gcdX a b
    let y := gcdY a b
    let z := gcdZ a b
    let a' := gcdA' a b
    let b' := gcdB' a b
    w * z = succPNat (x * y) ∧
      a = a' * d ∧
        b = b' * d ∧
          z * a' = succPNat (x * b') ∧
            w * b' = succPNat (y * a') ∧ (z * a : ℕ) = x * b + d ∧ (w * b : ℕ) = y * a + d := by
  intros d w x y z a' b'
  let u := XgcdType.start a b
  let ur := u.reduce

  have _ : d = ur.a := rfl
  have hb : d = ur.b := u.reduce_isReduced'
  have ha' : (a' : ℕ) = w + x := gcdA'_coe a b
  have hb' : (b' : ℕ) = y + z := gcdB'_coe a b
  have hdet : w * z = succPNat (x * y) := u.reduce_isSpecial' rfl
  constructor
  exact hdet
  have hdet' : (w * z : ℕ) = x * y + 1 := by rw [← mul_coe, hdet, succPNat_coe]
  have _ : u.v = ⟨a, b⟩ := XgcdType.start_v a b
  let hv : Prod.mk (w * d + x * ur.b : ℕ) (y * d + z * ur.b : ℕ) = ⟨a, b⟩ :=
    u.reduce_v.trans (XgcdType.start_v a b)
  rw [← hb, ← add_mul, ← add_mul, ← ha', ← hb'] at hv
  have ha'' : (a : ℕ) = a' * d := (congr_arg Prod.fst hv).symm
  have hb'' : (b : ℕ) = b' * d := (congr_arg Prod.snd hv).symm
  constructor
  exact eq ha''
  constructor
  exact eq hb''
  have hza' : (z * a' : ℕ) = x * b' + 1 := by
    rw [ha', hb', mul_add, mul_add, mul_comm (z : ℕ), hdet']
    ring
  have hwb' : (w * b' : ℕ) = y * a' + 1 := by
    rw [ha', hb', mul_add, mul_add, hdet']
    ring
  constructor
  · apply eq
    rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hza']
  

Proof state:
case right.right.right.right
a b : ℕ+
d : ℕ+ := gcdD a b
w : ℕ+ := gcdW a b
x : ℕ := gcdX a b
y : ℕ := gcdY a b
z : ℕ+ := gcdZ a b
a' : ℕ+ := gcdA' a b
b' : ℕ+ := gcdB' a b
u : XgcdType := XgcdType.start a b
ur : XgcdType := XgcdType.reduce u
x✝¹ : d = XgcdType.a ur
hb : d = XgcdType.b ur
ha' : ↑a' = ↑w + x
hb' : ↑b' = y + ↑z
hdet : w * z = succPNat (x * y)
hdet' : ↑w * ↑z = x * y + 1
x✝ : XgcdType.v u = (↑a, ↑b)
hv : (↑a' * ↑d, ↑b' * ↑d) = (↑a, ↑b)
ha'' : ↑a = ↑a' * ↑d
hb'' : ↑b = ↑b' * ↑d
hza' : ↑z * ↑a' = x * ↑b' + 1
hwb' : ↑w * ↑b' = y * ↑a' + 1
⊢ w * b' = succPNat (y * ↑a') ∧ ↑z * ↑a = x * ↑b + ↑d ∧ ↑w * ↑b = y * ↑a + ↑d

Next tactic:
constructor
theorem gcd_props :
    let d := gcdD a b
    let w := gcdW a b
    let x := gcdX a b
    let y := gcdY a b
    let z := gcdZ a b
    let a' := gcdA' a b
    let b' := gcdB' a b
    w * z = succPNat (x * y) ∧
      a = a' * d ∧
        b = b' * d ∧
          z * a' = succPNat (x * b') ∧
            w * b' = succPNat (y * a') ∧ (z * a : ℕ) = x * b + d ∧ (w * b : ℕ) = y * a + d := by
  intros d w x y z a' b'
  let u := XgcdType.start a b
  let ur := u.reduce

  have _ : d = ur.a := rfl
  have hb : d = ur.b := u.reduce_isReduced'
  have ha' : (a' : ℕ) = w + x := gcdA'_coe a b
  have hb' : (b' : ℕ) = y + z := gcdB'_coe a b
  have hdet : w * z = succPNat (x * y) := u.reduce_isSpecial' rfl
  constructor
  exact hdet
  have hdet' : (w * z : ℕ) = x * y + 1 := by rw [← mul_coe, hdet, succPNat_coe]
  have _ : u.v = ⟨a, b⟩ := XgcdType.start_v a b
  let hv : Prod.mk (w * d + x * ur.b : ℕ) (y * d + z * ur.b : ℕ) = ⟨a, b⟩ :=
    u.reduce_v.trans (XgcdType.start_v a b)
  rw [← hb, ← add_mul, ← add_mul, ← ha', ← hb'] at hv
  have ha'' : (a : ℕ) = a' * d := (congr_arg Prod.fst hv).symm
  have hb'' : (b : ℕ) = b' * d := (congr_arg Prod.snd hv).symm
  constructor
  exact eq ha''
  constructor
  exact eq hb''
  have hza' : (z * a' : ℕ) = x * b' + 1 := by
    rw [ha', hb', mul_add, mul_add, mul_comm (z : ℕ), hdet']
    ring
  have hwb' : (w * b' : ℕ) = y * a' + 1 := by
    rw [ha', hb', mul_add, mul_add, hdet']
    ring
  constructor
  · apply eq
    rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hza']
  constructor
  · 

Proof state:
case right.right.right.right.left
a b : ℕ+
d : ℕ+ := gcdD a b
w : ℕ+ := gcdW a b
x : ℕ := gcdX a b
y : ℕ := gcdY a b
z : ℕ+ := gcdZ a b
a' : ℕ+ := gcdA' a b
b' : ℕ+ := gcdB' a b
u : XgcdType := XgcdType.start a b
ur : XgcdType := XgcdType.reduce u
x✝¹ : d = XgcdType.a ur
hb : d = XgcdType.b ur
ha' : ↑a' = ↑w + x
hb' : ↑b' = y + ↑z
hdet : w * z = succPNat (x * y)
hdet' : ↑w * ↑z = x * y + 1
x✝ : XgcdType.v u = (↑a, ↑b)
hv : (↑a' * ↑d, ↑b' * ↑d) = (↑a, ↑b)
ha'' : ↑a = ↑a' * ↑d
hb'' : ↑b = ↑b' * ↑d
hza' : ↑z * ↑a' = x * ↑b' + 1
hwb' : ↑w * ↑b' = y * ↑a' + 1
⊢ w * b' = succPNat (y * ↑a')

Next tactic:
apply eq
theorem gcd_props :
    let d := gcdD a b
    let w := gcdW a b
    let x := gcdX a b
    let y := gcdY a b
    let z := gcdZ a b
    let a' := gcdA' a b
    let b' := gcdB' a b
    w * z = succPNat (x * y) ∧
      a = a' * d ∧
        b = b' * d ∧
          z * a' = succPNat (x * b') ∧
            w * b' = succPNat (y * a') ∧ (z * a : ℕ) = x * b + d ∧ (w * b : ℕ) = y * a + d := by
  intros d w x y z a' b'
  let u := XgcdType.start a b
  let ur := u.reduce

  have _ : d = ur.a := rfl
  have hb : d = ur.b := u.reduce_isReduced'
  have ha' : (a' : ℕ) = w + x := gcdA'_coe a b
  have hb' : (b' : ℕ) = y + z := gcdB'_coe a b
  have hdet : w * z = succPNat (x * y) := u.reduce_isSpecial' rfl
  constructor
  exact hdet
  have hdet' : (w * z : ℕ) = x * y + 1 := by rw [← mul_coe, hdet, succPNat_coe]
  have _ : u.v = ⟨a, b⟩ := XgcdType.start_v a b
  let hv : Prod.mk (w * d + x * ur.b : ℕ) (y * d + z * ur.b : ℕ) = ⟨a, b⟩ :=
    u.reduce_v.trans (XgcdType.start_v a b)
  rw [← hb, ← add_mul, ← add_mul, ← ha', ← hb'] at hv
  have ha'' : (a : ℕ) = a' * d := (congr_arg Prod.fst hv).symm
  have hb'' : (b : ℕ) = b' * d := (congr_arg Prod.snd hv).symm
  constructor
  exact eq ha''
  constructor
  exact eq hb''
  have hza' : (z * a' : ℕ) = x * b' + 1 := by
    rw [ha', hb', mul_add, mul_add, mul_comm (z : ℕ), hdet']
    ring
  have hwb' : (w * b' : ℕ) = y * a' + 1 := by
    rw [ha', hb', mul_add, mul_add, hdet']
    ring
  constructor
  · apply eq
    rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hza']
  constructor
  · apply eq
    

Proof state:
case right.right.right.right.left.a
a b : ℕ+
d : ℕ+ := gcdD a b
w : ℕ+ := gcdW a b
x : ℕ := gcdX a b
y : ℕ := gcdY a b
z : ℕ+ := gcdZ a b
a' : ℕ+ := gcdA' a b
b' : ℕ+ := gcdB' a b
u : XgcdType := XgcdType.start a b
ur : XgcdType := XgcdType.reduce u
x✝¹ : d = XgcdType.a ur
hb : d = XgcdType.b ur
ha' : ↑a' = ↑w + x
hb' : ↑b' = y + ↑z
hdet : w * z = succPNat (x * y)
hdet' : ↑w * ↑z = x * y + 1
x✝ : XgcdType.v u = (↑a, ↑b)
hv : (↑a' * ↑d, ↑b' * ↑d) = (↑a, ↑b)
ha'' : ↑a = ↑a' * ↑d
hb'' : ↑b = ↑b' * ↑d
hza' : ↑z * ↑a' = x * ↑b' + 1
hwb' : ↑w * ↑b' = y * ↑a' + 1
⊢ ↑(w * b') = ↑(succPNat (y * ↑a'))

Next tactic:
rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hwb']
theorem gcd_props :
    let d := gcdD a b
    let w := gcdW a b
    let x := gcdX a b
    let y := gcdY a b
    let z := gcdZ a b
    let a' := gcdA' a b
    let b' := gcdB' a b
    w * z = succPNat (x * y) ∧
      a = a' * d ∧
        b = b' * d ∧
          z * a' = succPNat (x * b') ∧
            w * b' = succPNat (y * a') ∧ (z * a : ℕ) = x * b + d ∧ (w * b : ℕ) = y * a + d := by
  intros d w x y z a' b'
  let u := XgcdType.start a b
  let ur := u.reduce

  have _ : d = ur.a := rfl
  have hb : d = ur.b := u.reduce_isReduced'
  have ha' : (a' : ℕ) = w + x := gcdA'_coe a b
  have hb' : (b' : ℕ) = y + z := gcdB'_coe a b
  have hdet : w * z = succPNat (x * y) := u.reduce_isSpecial' rfl
  constructor
  exact hdet
  have hdet' : (w * z : ℕ) = x * y + 1 := by rw [← mul_coe, hdet, succPNat_coe]
  have _ : u.v = ⟨a, b⟩ := XgcdType.start_v a b
  let hv : Prod.mk (w * d + x * ur.b : ℕ) (y * d + z * ur.b : ℕ) = ⟨a, b⟩ :=
    u.reduce_v.trans (XgcdType.start_v a b)
  rw [← hb, ← add_mul, ← add_mul, ← ha', ← hb'] at hv
  have ha'' : (a : ℕ) = a' * d := (congr_arg Prod.fst hv).symm
  have hb'' : (b : ℕ) = b' * d := (congr_arg Prod.snd hv).symm
  constructor
  exact eq ha''
  constructor
  exact eq hb''
  have hza' : (z * a' : ℕ) = x * b' + 1 := by
    rw [ha', hb', mul_add, mul_add, mul_comm (z : ℕ), hdet']
    ring
  have hwb' : (w * b' : ℕ) = y * a' + 1 := by
    rw [ha', hb', mul_add, mul_add, hdet']
    ring
  constructor
  · apply eq
    rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hza']
  constructor
  · apply eq
    rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hwb']
  

Proof state:
case right.right.right.right.right
a b : ℕ+
d : ℕ+ := gcdD a b
w : ℕ+ := gcdW a b
x : ℕ := gcdX a b
y : ℕ := gcdY a b
z : ℕ+ := gcdZ a b
a' : ℕ+ := gcdA' a b
b' : ℕ+ := gcdB' a b
u : XgcdType := XgcdType.start a b
ur : XgcdType := XgcdType.reduce u
x✝¹ : d = XgcdType.a ur
hb : d = XgcdType.b ur
ha' : ↑a' = ↑w + x
hb' : ↑b' = y + ↑z
hdet : w * z = succPNat (x * y)
hdet' : ↑w * ↑z = x * y + 1
x✝ : XgcdType.v u = (↑a, ↑b)
hv : (↑a' * ↑d, ↑b' * ↑d) = (↑a, ↑b)
ha'' : ↑a = ↑a' * ↑d
hb'' : ↑b = ↑b' * ↑d
hza' : ↑z * ↑a' = x * ↑b' + 1
hwb' : ↑w * ↑b' = y * ↑a' + 1
⊢ ↑z * ↑a = x * ↑b + ↑d ∧ ↑w * ↑b = y * ↑a + ↑d

Next tactic:
rw [ha'', hb'']
theorem gcd_props :
    let d := gcdD a b
    let w := gcdW a b
    let x := gcdX a b
    let y := gcdY a b
    let z := gcdZ a b
    let a' := gcdA' a b
    let b' := gcdB' a b
    w * z = succPNat (x * y) ∧
      a = a' * d ∧
        b = b' * d ∧
          z * a' = succPNat (x * b') ∧
            w * b' = succPNat (y * a') ∧ (z * a : ℕ) = x * b + d ∧ (w * b : ℕ) = y * a + d := by
  intros d w x y z a' b'
  let u := XgcdType.start a b
  let ur := u.reduce

  have _ : d = ur.a := rfl
  have hb : d = ur.b := u.reduce_isReduced'
  have ha' : (a' : ℕ) = w + x := gcdA'_coe a b
  have hb' : (b' : ℕ) = y + z := gcdB'_coe a b
  have hdet : w * z = succPNat (x * y) := u.reduce_isSpecial' rfl
  constructor
  exact hdet
  have hdet' : (w * z : ℕ) = x * y + 1 := by rw [← mul_coe, hdet, succPNat_coe]
  have _ : u.v = ⟨a, b⟩ := XgcdType.start_v a b
  let hv : Prod.mk (w * d + x * ur.b : ℕ) (y * d + z * ur.b : ℕ) = ⟨a, b⟩ :=
    u.reduce_v.trans (XgcdType.start_v a b)
  rw [← hb, ← add_mul, ← add_mul, ← ha', ← hb'] at hv
  have ha'' : (a : ℕ) = a' * d := (congr_arg Prod.fst hv).symm
  have hb'' : (b : ℕ) = b' * d := (congr_arg Prod.snd hv).symm
  constructor
  exact eq ha''
  constructor
  exact eq hb''
  have hza' : (z * a' : ℕ) = x * b' + 1 := by
    rw [ha', hb', mul_add, mul_add, mul_comm (z : ℕ), hdet']
    ring
  have hwb' : (w * b' : ℕ) = y * a' + 1 := by
    rw [ha', hb', mul_add, mul_add, hdet']
    ring
  constructor
  · apply eq
    rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hza']
  constructor
  · apply eq
    rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hwb']
  rw [ha'', hb'']
  

Proof state:
case right.right.right.right.right
a b : ℕ+
d : ℕ+ := gcdD a b
w : ℕ+ := gcdW a b
x : ℕ := gcdX a b
y : ℕ := gcdY a b
z : ℕ+ := gcdZ a b
a' : ℕ+ := gcdA' a b
b' : ℕ+ := gcdB' a b
u : XgcdType := XgcdType.start a b
ur : XgcdType := XgcdType.reduce u
x✝¹ : d = XgcdType.a ur
hb : d = XgcdType.b ur
ha' : ↑a' = ↑w + x
hb' : ↑b' = y + ↑z
hdet : w * z = succPNat (x * y)
hdet' : ↑w * ↑z = x * y + 1
x✝ : XgcdType.v u = (↑a, ↑b)
hv : (↑a' * ↑d, ↑b' * ↑d) = (↑a, ↑b)
ha'' : ↑a = ↑a' * ↑d
hb'' : ↑b = ↑b' * ↑d
hza' : ↑z * ↑a' = x * ↑b' + 1
hwb' : ↑w * ↑b' = y * ↑a' + 1
⊢ ↑z * (↑a' * ↑d) = x * (↑b' * ↑d) + ↑d ∧ ↑w * (↑b' * ↑d) = y * (↑a' * ↑d) + ↑d

Next tactic:
repeat' rw [← @mul_assoc]
theorem gcd_props :
    let d := gcdD a b
    let w := gcdW a b
    let x := gcdX a b
    let y := gcdY a b
    let z := gcdZ a b
    let a' := gcdA' a b
    let b' := gcdB' a b
    w * z = succPNat (x * y) ∧
      a = a' * d ∧
        b = b' * d ∧
          z * a' = succPNat (x * b') ∧
            w * b' = succPNat (y * a') ∧ (z * a : ℕ) = x * b + d ∧ (w * b : ℕ) = y * a + d := by
  intros d w x y z a' b'
  let u := XgcdType.start a b
  let ur := u.reduce

  have _ : d = ur.a := rfl
  have hb : d = ur.b := u.reduce_isReduced'
  have ha' : (a' : ℕ) = w + x := gcdA'_coe a b
  have hb' : (b' : ℕ) = y + z := gcdB'_coe a b
  have hdet : w * z = succPNat (x * y) := u.reduce_isSpecial' rfl
  constructor
  exact hdet
  have hdet' : (w * z : ℕ) = x * y + 1 := by rw [← mul_coe, hdet, succPNat_coe]
  have _ : u.v = ⟨a, b⟩ := XgcdType.start_v a b
  let hv : Prod.mk (w * d + x * ur.b : ℕ) (y * d + z * ur.b : ℕ) = ⟨a, b⟩ :=
    u.reduce_v.trans (XgcdType.start_v a b)
  rw [← hb, ← add_mul, ← add_mul, ← ha', ← hb'] at hv
  have ha'' : (a : ℕ) = a' * d := (congr_arg Prod.fst hv).symm
  have hb'' : (b : ℕ) = b' * d := (congr_arg Prod.snd hv).symm
  constructor
  exact eq ha''
  constructor
  exact eq hb''
  have hza' : (z * a' : ℕ) = x * b' + 1 := by
    rw [ha', hb', mul_add, mul_add, mul_comm (z : ℕ), hdet']
    ring
  have hwb' : (w * b' : ℕ) = y * a' + 1 := by
    rw [ha', hb', mul_add, mul_add, hdet']
    ring
  constructor
  · apply eq
    rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hza']
  constructor
  · apply eq
    rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hwb']
  rw [ha'', hb'']
  repeat' 

Proof state:
case right.right.right.right.right
a b : ℕ+
d : ℕ+ := gcdD a b
w : ℕ+ := gcdW a b
x : ℕ := gcdX a b
y : ℕ := gcdY a b
z : ℕ+ := gcdZ a b
a' : ℕ+ := gcdA' a b
b' : ℕ+ := gcdB' a b
u : XgcdType := XgcdType.start a b
ur : XgcdType := XgcdType.reduce u
x✝¹ : d = XgcdType.a ur
hb : d = XgcdType.b ur
ha' : ↑a' = ↑w + x
hb' : ↑b' = y + ↑z
hdet : w * z = succPNat (x * y)
hdet' : ↑w * ↑z = x * y + 1
x✝ : XgcdType.v u = (↑a, ↑b)
hv : (↑a' * ↑d, ↑b' * ↑d) = (↑a, ↑b)
ha'' : ↑a = ↑a' * ↑d
hb'' : ↑b = ↑b' * ↑d
hza' : ↑z * ↑a' = x * ↑b' + 1
hwb' : ↑w * ↑b' = y * ↑a' + 1
⊢ ↑z * (↑a' * ↑d) = x * (↑b' * ↑d) + ↑d ∧ ↑w * (↑b' * ↑d) = y * (↑a' * ↑d) + ↑d

Next tactic:
rw [← @mul_assoc]
theorem gcd_props :
    let d := gcdD a b
    let w := gcdW a b
    let x := gcdX a b
    let y := gcdY a b
    let z := gcdZ a b
    let a' := gcdA' a b
    let b' := gcdB' a b
    w * z = succPNat (x * y) ∧
      a = a' * d ∧
        b = b' * d ∧
          z * a' = succPNat (x * b') ∧
            w * b' = succPNat (y * a') ∧ (z * a : ℕ) = x * b + d ∧ (w * b : ℕ) = y * a + d := by
  intros d w x y z a' b'
  let u := XgcdType.start a b
  let ur := u.reduce

  have _ : d = ur.a := rfl
  have hb : d = ur.b := u.reduce_isReduced'
  have ha' : (a' : ℕ) = w + x := gcdA'_coe a b
  have hb' : (b' : ℕ) = y + z := gcdB'_coe a b
  have hdet : w * z = succPNat (x * y) := u.reduce_isSpecial' rfl
  constructor
  exact hdet
  have hdet' : (w * z : ℕ) = x * y + 1 := by rw [← mul_coe, hdet, succPNat_coe]
  have _ : u.v = ⟨a, b⟩ := XgcdType.start_v a b
  let hv : Prod.mk (w * d + x * ur.b : ℕ) (y * d + z * ur.b : ℕ) = ⟨a, b⟩ :=
    u.reduce_v.trans (XgcdType.start_v a b)
  rw [← hb, ← add_mul, ← add_mul, ← ha', ← hb'] at hv
  have ha'' : (a : ℕ) = a' * d := (congr_arg Prod.fst hv).symm
  have hb'' : (b : ℕ) = b' * d := (congr_arg Prod.snd hv).symm
  constructor
  exact eq ha''
  constructor
  exact eq hb''
  have hza' : (z * a' : ℕ) = x * b' + 1 := by
    rw [ha', hb', mul_add, mul_add, mul_comm (z : ℕ), hdet']
    ring
  have hwb' : (w * b' : ℕ) = y * a' + 1 := by
    rw [ha', hb', mul_add, mul_add, hdet']
    ring
  constructor
  · apply eq
    rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hza']
  constructor
  · apply eq
    rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hwb']
  rw [ha'', hb'']
  repeat' 

Proof state:
case right.right.right.right.right
a b : ℕ+
d : ℕ+ := gcdD a b
w : ℕ+ := gcdW a b
x : ℕ := gcdX a b
y : ℕ := gcdY a b
z : ℕ+ := gcdZ a b
a' : ℕ+ := gcdA' a b
b' : ℕ+ := gcdB' a b
u : XgcdType := XgcdType.start a b
ur : XgcdType := XgcdType.reduce u
x✝¹ : d = XgcdType.a ur
hb : d = XgcdType.b ur
ha' : ↑a' = ↑w + x
hb' : ↑b' = y + ↑z
hdet : w * z = succPNat (x * y)
hdet' : ↑w * ↑z = x * y + 1
x✝ : XgcdType.v u = (↑a, ↑b)
hv : (↑a' * ↑d, ↑b' * ↑d) = (↑a, ↑b)
ha'' : ↑a = ↑a' * ↑d
hb'' : ↑b = ↑b' * ↑d
hza' : ↑z * ↑a' = x * ↑b' + 1
hwb' : ↑w * ↑b' = y * ↑a' + 1
⊢ ↑z * ↑a' * ↑d = x * (↑b' * ↑d) + ↑d ∧ ↑w * (↑b' * ↑d) = y * (↑a' * ↑d) + ↑d

Next tactic:
rw [← @mul_assoc]
theorem gcd_props :
    let d := gcdD a b
    let w := gcdW a b
    let x := gcdX a b
    let y := gcdY a b
    let z := gcdZ a b
    let a' := gcdA' a b
    let b' := gcdB' a b
    w * z = succPNat (x * y) ∧
      a = a' * d ∧
        b = b' * d ∧
          z * a' = succPNat (x * b') ∧
            w * b' = succPNat (y * a') ∧ (z * a : ℕ) = x * b + d ∧ (w * b : ℕ) = y * a + d := by
  intros d w x y z a' b'
  let u := XgcdType.start a b
  let ur := u.reduce

  have _ : d = ur.a := rfl
  have hb : d = ur.b := u.reduce_isReduced'
  have ha' : (a' : ℕ) = w + x := gcdA'_coe a b
  have hb' : (b' : ℕ) = y + z := gcdB'_coe a b
  have hdet : w * z = succPNat (x * y) := u.reduce_isSpecial' rfl
  constructor
  exact hdet
  have hdet' : (w * z : ℕ) = x * y + 1 := by rw [← mul_coe, hdet, succPNat_coe]
  have _ : u.v = ⟨a, b⟩ := XgcdType.start_v a b
  let hv : Prod.mk (w * d + x * ur.b : ℕ) (y * d + z * ur.b : ℕ) = ⟨a, b⟩ :=
    u.reduce_v.trans (XgcdType.start_v a b)
  rw [← hb, ← add_mul, ← add_mul, ← ha', ← hb'] at hv
  have ha'' : (a : ℕ) = a' * d := (congr_arg Prod.fst hv).symm
  have hb'' : (b : ℕ) = b' * d := (congr_arg Prod.snd hv).symm
  constructor
  exact eq ha''
  constructor
  exact eq hb''
  have hza' : (z * a' : ℕ) = x * b' + 1 := by
    rw [ha', hb', mul_add, mul_add, mul_comm (z : ℕ), hdet']
    ring
  have hwb' : (w * b' : ℕ) = y * a' + 1 := by
    rw [ha', hb', mul_add, mul_add, hdet']
    ring
  constructor
  · apply eq
    rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hza']
  constructor
  · apply eq
    rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hwb']
  rw [ha'', hb'']
  repeat' 

Proof state:
case right.right.right.right.right
a b : ℕ+
d : ℕ+ := gcdD a b
w : ℕ+ := gcdW a b
x : ℕ := gcdX a b
y : ℕ := gcdY a b
z : ℕ+ := gcdZ a b
a' : ℕ+ := gcdA' a b
b' : ℕ+ := gcdB' a b
u : XgcdType := XgcdType.start a b
ur : XgcdType := XgcdType.reduce u
x✝¹ : d = XgcdType.a ur
hb : d = XgcdType.b ur
ha' : ↑a' = ↑w + x
hb' : ↑b' = y + ↑z
hdet : w * z = succPNat (x * y)
hdet' : ↑w * ↑z = x * y + 1
x✝ : XgcdType.v u = (↑a, ↑b)
hv : (↑a' * ↑d, ↑b' * ↑d) = (↑a, ↑b)
ha'' : ↑a = ↑a' * ↑d
hb'' : ↑b = ↑b' * ↑d
hza' : ↑z * ↑a' = x * ↑b' + 1
hwb' : ↑w * ↑b' = y * ↑a' + 1
⊢ ↑z * ↑a' * ↑d = x * ↑b' * ↑d + ↑d ∧ ↑w * (↑b' * ↑d) = y * (↑a' * ↑d) + ↑d

Next tactic:
rw [← @mul_assoc]
theorem gcd_props :
    let d := gcdD a b
    let w := gcdW a b
    let x := gcdX a b
    let y := gcdY a b
    let z := gcdZ a b
    let a' := gcdA' a b
    let b' := gcdB' a b
    w * z = succPNat (x * y) ∧
      a = a' * d ∧
        b = b' * d ∧
          z * a' = succPNat (x * b') ∧
            w * b' = succPNat (y * a') ∧ (z * a : ℕ) = x * b + d ∧ (w * b : ℕ) = y * a + d := by
  intros d w x y z a' b'
  let u := XgcdType.start a b
  let ur := u.reduce

  have _ : d = ur.a := rfl
  have hb : d = ur.b := u.reduce_isReduced'
  have ha' : (a' : ℕ) = w + x := gcdA'_coe a b
  have hb' : (b' : ℕ) = y + z := gcdB'_coe a b
  have hdet : w * z = succPNat (x * y) := u.reduce_isSpecial' rfl
  constructor
  exact hdet
  have hdet' : (w * z : ℕ) = x * y + 1 := by rw [← mul_coe, hdet, succPNat_coe]
  have _ : u.v = ⟨a, b⟩ := XgcdType.start_v a b
  let hv : Prod.mk (w * d + x * ur.b : ℕ) (y * d + z * ur.b : ℕ) = ⟨a, b⟩ :=
    u.reduce_v.trans (XgcdType.start_v a b)
  rw [← hb, ← add_mul, ← add_mul, ← ha', ← hb'] at hv
  have ha'' : (a : ℕ) = a' * d := (congr_arg Prod.fst hv).symm
  have hb'' : (b : ℕ) = b' * d := (congr_arg Prod.snd hv).symm
  constructor
  exact eq ha''
  constructor
  exact eq hb''
  have hza' : (z * a' : ℕ) = x * b' + 1 := by
    rw [ha', hb', mul_add, mul_add, mul_comm (z : ℕ), hdet']
    ring
  have hwb' : (w * b' : ℕ) = y * a' + 1 := by
    rw [ha', hb', mul_add, mul_add, hdet']
    ring
  constructor
  · apply eq
    rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hza']
  constructor
  · apply eq
    rw [succPNat_coe, Nat.succ_eq_add_one, mul_coe, hwb']
  rw [ha'', hb'']
  repeat' 

Proof state:
case right.right.right.right.right
a b : ℕ+
d : ℕ+ := gcdD a b
w : ℕ+ := gcdW a b
x : ℕ := gcdX a b
y : ℕ := gcdY a b
z : ℕ+ := gcdZ a b
a' : ℕ+ := gcdA' a b
b' : ℕ+ := gcdB' a b
u : XgcdType := XgcdType.start a b
ur : XgcdType := XgcdType.reduce u
x✝¹ : d = XgcdType.a ur
hb : d = XgcdType.b ur
ha' : ↑a' = ↑w + x
hb' : ↑b' = y + ↑z
hdet : w * z = succPNat (x * y)
hdet' : ↑w * ↑z = x * y + 1
x✝ : XgcdType.v u = (↑a, ↑b)
hv : (↑a' * ↑d, ↑b' * ↑d) = (↑a, ↑b)
ha'' : ↑a = ↑a' * ↑d
hb'' : ↑b = ↑b' * ↑d
hza' : ↑z * ↑a' = x * ↑b' + 1
hwb' : ↑w * ↑b' = y * ↑a' + 1
⊢ ↑z * ↑a' * ↑d = x * ↑b' * ↑d + ↑d ∧ ↑w * ↑b' * ↑d = y * (↑a' * ↑d) + ↑d

Next tactic:
rw [← @mul_assoc]