awhecmu/canonical-drafter-extract-mathlib huggingface dataset:
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (hypothesis)
Goal:
K : Type u_1
g : GenContFract K
inst : Field K
a b : K
b_ne_zero : b ≠ 0
n' : ℕ
nth_partDen_ne_zero : ∀ {b : K}, g.partDens.get? (n' + 1) = some b → b ≠ 0
not_terminatedAt_n : ¬g.TerminatedAt (n' + 1)
s_nth_eq : g.s.get? (n' + 1) = some { a := a, b := b }
pa pb : K
s_n'th_eq : g.s.get? n' = some { a := pa, b := pb }
g' : GenContFract K := g.squashGCF (n' + 1)
pred_conts : Pair K := g.contsAux (n' + 1)
succ_n'th_contsAux_eq : pred_conts = g.contsAux (n' + 1)
ppred_conts : Pair K := g.contsAux n'
n'th_contsAux_eq : ppred_conts = g.contsAux n'
pA : K := pred_conts.a
pB : K := pred_conts.b
ppA : K := ppred_conts.a
ppB : K := ppred_conts.b
pred_conts' : Pair K := g'.contsAux (n' + 1)
succ_n'th_contsAux_eq' : pred_conts' = g'.contsAux (n' + 1)
ppred_conts' : Pair K := g'.contsAux n'
n'th_contsAux_eq' : ppred_conts' = g'.contsAux n'
pA' : K := pred_conts'.a
pB' : K := pred_conts'.b
ppA' : K := ppred_conts'.a
ppB' : K := ppred_conts'.b
this_1 : g'.convs (n' + 1) = ((pb + a / b) * pA' + pa * ppA') / ((pb + a / b) * pB' + pa * ppB')
this_2 : g.convs (n' + 2) = (b * (pb * pA + pa * ppA) + a * pA) / (b * (pb * pB + pa * ppB) + a * pB)
this :
  ((pb + a / b) * pA + pa * ppA) / ((pb + a / b) * pB + pa * ppB) =
    (b * (pb * pA + pa * ppA) + a * pA) / (b * (pb * pB + pa * ppB) + a * pB)
eq1 : pA' = pA
eq2 : pB' = pB
eq3 : ppA' = ppA
⊢ (b * (pb * pA + pa * ppA) + a * pA) / (b * (pb * pB + pa * ppB) + a * pB) =
    ((pb + a / b) * pA' + pa * ppA') / ((pb + a / b) * pB' + pa * ppB')
have eq4 : ppB' = ppB
Tactic: obtain ⟨eq1, eq2, eq3, eq4⟩ : pA' = pA ∧ pB' = pB ∧ ppA' = ppA ∧ ppB' = ppB := by
          simp [*, g', pA, pB, ppA, ppB, pA', pB', ppA', ppB',
            (contsAux_eq_contsAux_squashGCF_of_le <| le_refl <| n' + 1).symm,
            (contsAux_eq_contsAux_squashGCF_of_le n'.le_succ).symm]
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
g : GenContFract K
inst : Field K
a b : K
b_ne_zero : b ≠ 0
n' : ℕ
nth_partDen_ne_zero : ∀ {b : K}, g.partDens.get? (n' + 1) = some b → b ≠ 0
not_terminatedAt_n : ¬g.TerminatedAt (n' + 1)
s_nth_eq : g.s.get? (n' + 1) = some { a := a, b := b }
pa pb : K
s_n'th_eq : g.s.get? n' = some { a := pa, b := pb }
g' : GenContFract K := g.squashGCF (n' + 1)
pred_conts : Pair K := g.contsAux (n' + 1)
succ_n'th_contsAux_eq : pred_conts = g.contsAux (n' + 1)
ppred_conts : Pair K := g.contsAux n'
n'th_contsAux_eq : ppred_conts = g.contsAux n'
pA : K := pred_conts.a
pB : K := pred_conts.b
ppA : K := ppred_conts.a
ppB : K := ppred_conts.b
pred_conts' : Pair K := g'.contsAux (n' + 1)
succ_n'th_contsAux_eq' : pred_conts' = g'.contsAux (n' + 1)
ppred_conts' : Pair K := g'.contsAux n'
n'th_contsAux_eq' : ppred_conts' = g'.contsAux n'
pA' : K := pred_conts'.a
pB' : K := pred_conts'.b
ppA' : K := ppred_conts'.a
ppB' : K := ppred_conts'.b
this_1 : g'.convs (n' + 1) = ((pb + a / b) * pA' + pa * ppA') / ((pb + a / b) * pB' + pa * ppB')
this_2 : g.convs (n' + 2) = (b * (pb * pA + pa * ppA) + a * pA) / (b * (pb * pB + pa * ppB) + a * pB)
this :
  ((pb + a / b) * pA + pa * ppA) / ((pb + a / b) * pB + pa * ppB) =
    (b * (pb * pA + pa * ppA) + a * pA) / (b * (pb * pB + pa * ppB) + a * pB)
eq1 : pA' = pA
eq2 : pB' = pB
eq3 : ppA' = ppA
eq4 : ppB' = ppB
⊢ (b * (pb * pA + pa * ppA) + a * pA) / (b * (pb * pB + pa * ppB) + a * pB) =
    ((pb + a / b) * pA' + pa * ppA') / ((pb + a / b) * pB' + pa * ppB')
have symm : ((pb + a / b) * pA' + pa * ppA') / ((pb + a / b) * pB' + pa * ppB') =
  (b * (pb * pA + pa * ppA) + a * pA) / (b * (pb * pB + pa * ppB) + a * pB)
Tactic: symm
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
g : GenContFract K
inst : Field K
a b : K
b_ne_zero : b ≠ 0
n' : ℕ
nth_partDen_ne_zero : ∀ {b : K}, g.partDens.get? (n' + 1) = some b → b ≠ 0
not_terminatedAt_n : ¬g.TerminatedAt (n' + 1)
s_nth_eq : g.s.get? (n' + 1) = some { a := a, b := b }
pa pb : K
s_n'th_eq : g.s.get? n' = some { a := pa, b := pb }
g' : GenContFract K := g.squashGCF (n' + 1)
pred_conts : Pair K := g.contsAux (n' + 1)
succ_n'th_contsAux_eq : pred_conts = g.contsAux (n' + 1)
ppred_conts : Pair K := g.contsAux n'
n'th_contsAux_eq : ppred_conts = g.contsAux n'
pA : K := pred_conts.a
pB : K := pred_conts.b
ppA : K := ppred_conts.a
ppB : K := ppred_conts.b
pred_conts' : Pair K := g'.contsAux (n' + 1)
succ_n'th_contsAux_eq' : pred_conts' = g'.contsAux (n' + 1)
ppred_conts' : Pair K := g'.contsAux n'
n'th_contsAux_eq' : ppred_conts' = g'.contsAux n'
pA' : K := pred_conts'.a
pB' : K := pred_conts'.b
ppA' : K := ppred_conts'.a
ppB' : K := ppred_conts'.b
this_1 : g'.convs (n' + 1) = ((pb + a / b) * pA' + pa * ppA') / ((pb + a / b) * pB' + pa * ppB')
this : g.convs (n' + 2) = (b * (pb * pA + pa * ppA) + a * pA) / (b * (pb * pB + pa * ppB) + a * pB)
⊢ (b * (pb * pA + pa * ppA) + a * pA) / (b * (pb * pB + pa * ppB) + a * pB) =
    ((pb + a / b) * pA' + pa * ppA') / ((pb + a / b) * pB' + pa * ppB')
have inr : ((pb + a / b) * pA + pa * ppA) / ((pb + a / b) * pB + pa * ppB) =
  (b * (pb * pA + pa * ppA) + a * pA) / (b * (pb * pB + pa * ppB) + a * pB)
Tactic: suffices
        ((pb + a / b) * pA + pa * ppA) / ((pb + a / b) * pB + pa * ppB) =
          (b * (pb * pA + pa * ppA) + a * pA) / (b * (pb * pB + pa * ppB) + a * pB) by
        obtain ⟨eq1, eq2, eq3, eq4⟩ : pA' = pA ∧ pB' = pB ∧ ppA' = ppA ∧ ppB' = ppB := by
          simp [*, g', pA, pB, ppA, ppB, pA', pB', ppA', ppB',
            (contsAux_eq_contsAux_squashGCF_of_le <| le_refl <| n' + 1).symm,
            (contsAux_eq_contsAux_squashGCF_of_le n'.le_succ).symm]
        symm
        simpa only [eq1, eq2, eq3, eq4, mul_div_cancel_right₀ _ b_ne_zero]
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
n : ℕ
IH :
  ∀ {g : GenContFract K} (s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs n = g.convs' n
g : GenContFract K
s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n + 1 → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF n
⊢ g.convs (n + 1) = g.convs' (n + 1)
have succ : g.convs (n + 1) = g'.convs' n
Tactic: suffices g.convs (n + 1) = g'.convs' n by
      rwa [succ_nth_conv'_eq_squashGCF_nth_conv']
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
n : ℕ
IH :
  ∀ {g : GenContFract K} (s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs n = g.convs' n
g : GenContFract K
s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n + 1 → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF n
⊢ g.convs (n + 1) = g'.convs' n
have succ : ∀ (terminatedAt_n : g.TerminatedAt n), g.convs (n + 1) = g'.convs' n
Tactic: rcases Decidable.em (TerminatedAt g n) with terminatedAt_n | not_terminatedAt_n
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
n : ℕ
IH :
  ∀ {g : GenContFract K} (s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs n = g.convs' n
g : GenContFract K
s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n + 1 → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF n
succ : ∀ (terminatedAt_n : g.TerminatedAt n), g.convs (n + 1) = g'.convs' n
⊢ g.convs (n + 1) = g'.convs' n
have succ₁ : ∀ (not_terminatedAt_n : ¬g.TerminatedAt n), g.convs (n + 1) = g'.convs' n
Tactic: rcases Decidable.em (TerminatedAt g n) with terminatedAt_n | not_terminatedAt_n
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (hypothesis)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
n : ℕ
IH :
  ∀ {g : GenContFract K} (s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs n = g.convs' n
g : GenContFract K
s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n + 1 → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF n
terminatedAt_n : g.TerminatedAt n
⊢ g.convs (n + 1) = g'.convs' n
have g'_eq_g : g' = g
Tactic: have g'_eq_g : g' = g := squashGCF_eq_self_of_terminated terminatedAt_n
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
n : ℕ
IH :
  ∀ {g : GenContFract K} (s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs n = g.convs' n
g : GenContFract K
s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n + 1 → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF n
terminatedAt_n : g.TerminatedAt n
g'_eq_g : g' = g
⊢ g.convs (n + 1) = g'.convs' n
have rw : ∀ {gp : Pair K} {m : ℕ}, m < n → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b
Tactic: rw [convs_stable_of_terminated n.le_succ terminatedAt_n, g'_eq_g, IH _]
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
n : ℕ
IH :
  ∀ {g : GenContFract K} (s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs n = g.convs' n
g : GenContFract K
s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n + 1 → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF n
not_terminatedAt_n : ¬g.TerminatedAt n
this : g.convs (n + 1) = g'.convs n
⊢ g.convs (n + 1) = g'.convs' n
have rwa : ∀ {gp : Pair K} {m : ℕ}, m < n → g'.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b
Tactic: rwa [← IH]
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
n : ℕ
IH :
  ∀ {g : GenContFract K} (s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs n = g.convs' n
g : GenContFract K
s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n + 1 → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF n
not_terminatedAt_n : ¬g.TerminatedAt n
this : g.convs (n + 1) = g'.convs n
gp' : Pair K
m : ℕ
m_lt_n : m < n
s_mth_eq' : g'.s.get? m = some gp'
⊢ 0 < gp'.a ∧ 0 < gp'.b
have refl : ∀
  (IH :
    ∀ {g : GenContFract K}
      (s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b),
      g.convs m.succ = g.convs' m.succ)
  (s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ + 1 → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b),
  let g' := g.squashGCF m.succ;
  ∀ (not_terminatedAt_n : ¬g.TerminatedAt m.succ) (this : g.convs (m.succ + 1) = g'.convs m.succ)
    (s_mth_eq' : g'.s.get? m = some gp'), 0 < gp'.a ∧ 0 < gp'.b
Tactic: rcases m_lt_n with n | succ_m_lt_n
Cleared hypotheses: n, IH, s_pos, g', not_terminatedAt_n, this, m_lt_n, s_mth_eq'
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
n : ℕ
IH :
  ∀ {g : GenContFract K} (s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs n = g.convs' n
g : GenContFract K
s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n + 1 → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF n
not_terminatedAt_n : ¬g.TerminatedAt n
this : g.convs (n + 1) = g'.convs n
gp' : Pair K
m : ℕ
m_lt_n : m < n
s_mth_eq' : g'.s.get? m = some gp'
refl :
  ∀
    (IH :
      ∀ {g : GenContFract K}
        (s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b),
        g.convs m.succ = g.convs' m.succ)
    (s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ + 1 → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b),
    let g' := g.squashGCF m.succ;
    ∀ (not_terminatedAt_n : ¬g.TerminatedAt m.succ) (this : g.convs (m.succ + 1) = g'.convs m.succ)
      (s_mth_eq' : g'.s.get? m = some gp'), 0 < gp'.a ∧ 0 < gp'.b
⊢ 0 < gp'.a ∧ 0 < gp'.b
have step : ∀ {m_1 : ℕ} (succ_m_lt_n : m.succ.le m_1)
  (IH :
    ∀ {g : GenContFract K} (s_pos : ∀ {gp : Pair K} {m : ℕ}, m < m_1.succ → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b),
      g.convs m_1.succ = g.convs' m_1.succ)
  (s_pos : ∀ {gp : Pair K} {m : ℕ}, m < m_1.succ + 1 → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b),
  let g' := g.squashGCF m_1.succ;
  ∀ (not_terminatedAt_n : ¬g.TerminatedAt m_1.succ) (this : g.convs (m_1.succ + 1) = g'.convs m_1.succ)
    (s_mth_eq' : g'.s.get? m = some gp'), 0 < gp'.a ∧ 0 < gp'.b
Tactic: rcases m_lt_n with n | succ_m_lt_n
Cleared hypotheses: n, IH, s_pos, g', not_terminatedAt_n, this, m_lt_n, s_mth_eq'
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
g : GenContFract K
gp' : Pair K
m : ℕ
IH :
  ∀ {g : GenContFract K}
    (s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs m.succ = g.convs' m.succ
s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ + 1 → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF m.succ
not_terminatedAt_n : ¬g.TerminatedAt m.succ
this : g.convs (m.succ + 1) = g'.convs m.succ
s_mth_eq' : g'.s.get? m = some gp'
⊢ 0 < gp'.a ∧ 0 < gp'.b
have refl : ∀ (gp_succ_m : Pair K) (s_succ_mth_eq : g.s.get? (m + 1) = some gp_succ_m), 0 < gp'.a ∧ 0 < gp'.b
Tactic: obtain ⟨gp_succ_m, s_succ_mth_eq⟩ : ∃ gp_succ_m, g.s.get? (m + 1) = some gp_succ_m :=
            Option.ne_none_iff_exists'.mp not_terminatedAt_n
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
g : GenContFract K
gp' : Pair K
m : ℕ
IH :
  ∀ {g : GenContFract K}
    (s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs m.succ = g.convs' m.succ
s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ + 1 → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF m.succ
not_terminatedAt_n : ¬g.TerminatedAt m.succ
this : g.convs (m.succ + 1) = g'.convs m.succ
s_mth_eq' : g'.s.get? m = some gp'
gp_succ_m : Pair K
s_succ_mth_eq : g.s.get? (m + 1) = some gp_succ_m
⊢ 0 < gp'.a ∧ 0 < gp'.b
have refl : ∀ (gp_m : Pair K) (mth_s_eq : g.s.get? m = some gp_m), 0 < gp'.a ∧ 0 < gp'.b
Tactic: obtain ⟨gp_m, mth_s_eq⟩ : ∃ gp_m, g.s.get? m = some gp_m :=
            g.s.ge_stable m.le_succ s_succ_mth_eq
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (hypothesis)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
g : GenContFract K
gp' : Pair K
m : ℕ
IH :
  ∀ {g : GenContFract K}
    (s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs m.succ = g.convs' m.succ
s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ + 1 → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF m.succ
not_terminatedAt_n : ¬g.TerminatedAt m.succ
this_1 : g.convs (m.succ + 1) = g'.convs m.succ
s_mth_eq' : g'.s.get? m = some gp'
gp_succ_m : Pair K
s_succ_mth_eq : g.s.get? (m + 1) = some gp_succ_m
gp_m : Pair K
mth_s_eq : g.s.get? m = some gp_m
this : 0 < gp_m.a ∧ 0 < gp_m.b + gp_succ_m.a / gp_succ_m.b
⊢ 0 < gp'.a ∧ 0 < gp'.b
have ot : g'.s.get? m = some { a := gp_m.a, b := gp_m.b + gp_succ_m.a / gp_succ_m.b }
Tactic: have ot : g'.s.get? m = some ⟨gp_m.a, gp_m.b + gp_succ_m.a / gp_succ_m.b⟩ :=
              squashSeq_nth_of_not_terminated mth_s_eq s_succ_mth_eq
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
g : GenContFract K
gp' : Pair K
m : ℕ
IH :
  ∀ {g : GenContFract K}
    (s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs m.succ = g.convs' m.succ
s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ + 1 → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF m.succ
not_terminatedAt_n : ¬g.TerminatedAt m.succ
this : g.convs (m.succ + 1) = g'.convs m.succ
s_mth_eq' : g'.s.get? m = some gp'
gp_succ_m : Pair K
s_succ_mth_eq : g.s.get? (m + 1) = some gp_succ_m
gp_m : Pair K
mth_s_eq : g.s.get? m = some gp_m
⊢ 0 < gp'.a ∧ 0 < gp'.b
have refl : 0 < gp_m.a ∧ 0 < gp_m.b + gp_succ_m.a / gp_succ_m.b
Tactic: suffices 0 < gp_m.a ∧ 0 < gp_m.b + gp_succ_m.a / gp_succ_m.b by
            have ot : g'.s.get? m = some ⟨gp_m.a, gp_m.b + gp_succ_m.a / gp_succ_m.b⟩ :=
              squashSeq_nth_of_not_terminated mth_s_eq s_succ_mth_eq
            grind
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (hypothesis)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
g : GenContFract K
gp' : Pair K
m : ℕ
IH :
  ∀ {g : GenContFract K}
    (s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs m.succ = g.convs' m.succ
s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ + 1 → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF m.succ
not_terminatedAt_n : ¬g.TerminatedAt m.succ
this : g.convs (m.succ + 1) = g'.convs m.succ
s_mth_eq' : g'.s.get? m = some gp'
gp_succ_m : Pair K
s_succ_mth_eq : g.s.get? (m + 1) = some gp_succ_m
gp_m : Pair K
mth_s_eq : g.s.get? m = some gp_m
⊢ 0 < gp_m.a ∧ 0 < gp_m.b + gp_succ_m.a / gp_succ_m.b
have m_lt_n : m < m.succ
Tactic: have m_lt_n : m < m.succ := Nat.lt_succ_self m
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
g : GenContFract K
gp' : Pair K
m : ℕ
IH :
  ∀ {g : GenContFract K}
    (s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs m.succ = g.convs' m.succ
s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ + 1 → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF m.succ
not_terminatedAt_n : ¬g.TerminatedAt m.succ
this : g.convs (m.succ + 1) = g'.convs m.succ
s_mth_eq' : g'.s.get? m = some gp'
gp_succ_m : Pair K
s_succ_mth_eq : g.s.get? (m + 1) = some gp_succ_m
gp_m : Pair K
mth_s_eq : g.s.get? m = some gp_m
m_lt_n : m < m.succ
⊢ 0 < gp_m.a ∧ 0 < gp_m.b + gp_succ_m.a / gp_succ_m.b
have refl : 0 < gp_m.b + gp_succ_m.a / gp_succ_m.b
Tactic: refine ⟨(s_pos (Nat.lt_succ_of_lt m_lt_n) mth_s_eq).left, ?_⟩
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
g : GenContFract K
gp' : Pair K
m : ℕ
IH :
  ∀ {g : GenContFract K}
    (s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs m.succ = g.convs' m.succ
s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ + 1 → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF m.succ
not_terminatedAt_n : ¬g.TerminatedAt m.succ
this : g.convs (m.succ + 1) = g'.convs m.succ
s_mth_eq' : g'.s.get? m = some gp'
gp_succ_m : Pair K
s_succ_mth_eq : g.s.get? (m + 1) = some gp_succ_m
gp_m : Pair K
mth_s_eq : g.s.get? m = some gp_m
m_lt_n : m < m.succ
⊢ 0 < gp_m.b + gp_succ_m.a / gp_succ_m.b
have refl : 0 < gp_succ_m.a / gp_succ_m.b
Tactic: refine add_pos (s_pos (Nat.lt_succ_of_lt m_lt_n) mth_s_eq).right ?_
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (hypothesis)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
g : GenContFract K
gp' : Pair K
m : ℕ
IH :
  ∀ {g : GenContFract K}
    (s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs m.succ = g.convs' m.succ
s_pos : ∀ {gp : Pair K} {m_1 : ℕ}, m_1 < m.succ + 1 → g.s.get? m_1 = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF m.succ
not_terminatedAt_n : ¬g.TerminatedAt m.succ
this : g.convs (m.succ + 1) = g'.convs m.succ
s_mth_eq' : g'.s.get? m = some gp'
gp_succ_m : Pair K
s_succ_mth_eq : g.s.get? (m + 1) = some gp_succ_m
gp_m : Pair K
mth_s_eq : g.s.get? m = some gp_m
m_lt_n : m < m.succ
⊢ 0 < gp_succ_m.a / gp_succ_m.b
have this₁ : 0 < gp_succ_m.a ∧ 0 < gp_succ_m.b
Tactic: have : 0 < gp_succ_m.a ∧ 0 < gp_succ_m.b := s_pos (lt_add_one <| m + 1) s_succ_mth_eq
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
g : GenContFract K
gp' : Pair K
m m_1 : ℕ
succ_m_lt_n : m.succ.le m_1
IH :
  ∀ {g : GenContFract K} (s_pos : ∀ {gp : Pair K} {m : ℕ}, m < m_1.succ → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs m_1.succ = g.convs' m_1.succ
s_pos : ∀ {gp : Pair K} {m : ℕ}, m < m_1.succ + 1 → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF m_1.succ
not_terminatedAt_n : ¬g.TerminatedAt m_1.succ
this : g.convs (m_1.succ + 1) = g'.convs m_1.succ
s_mth_eq' : g'.s.get? m = some gp'
⊢ 0 < gp'.a ∧ 0 < gp'.b
have step : g.s.get? m = some gp'
Tactic: refine s_pos (Nat.lt_succ_of_lt <| Nat.lt_succ_of_lt succ_m_lt_n) ?_
-- Lean 4 proof step from Mathlib.Algebra.ContinuedFractions.ConvergentsEquiv (goal)
Goal:
K : Type u_1
inst : Field K
inst_1 : LinearOrder K
inst_2 : IsStrictOrderedRing K
n : ℕ
IH :
  ∀ {g : GenContFract K} (s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b),
    g.convs n = g.convs' n
g : GenContFract K
s_pos : ∀ {gp : Pair K} {m : ℕ}, m < n + 1 → g.s.get? m = some gp → 0 < gp.a ∧ 0 < gp.b
g' : GenContFract K := g.squashGCF n
not_terminatedAt_n : ¬g.TerminatedAt n
⊢ g.convs (n + 1) = g'.convs' n
have succ : g.convs (n + 1) = g'.convs n
Tactic: suffices g.convs (n + 1) = g'.convs n by
        -- invoke the IH for the squashed gcf
        rwa [← IH]
        intro gp' m m_lt_n s_mth_eq'
        -- case distinction on m + 1 = n or m + 1 < n
        rcases m_lt_n with n | succ_m_lt_n
        · -- the difficult case at the squashed position: we first obtain the values from
          -- the sequence
          obtain ⟨gp_succ_m, s_succ_mth_eq⟩ : ∃ gp_succ_m, g.s.get? (m + 1) = some gp_succ_m :=
            Option.ne_none_iff_exists'.mp not_terminatedAt_n
          obtain ⟨gp_m, mth_s_eq⟩ : ∃ gp_m, g.s.get? m = some gp_m :=
            g.s.ge_stable m.le_succ s_succ_mth_eq
          -- we then plug them into the recurrence
          suffices 0 < gp_m.a ∧ 0 < gp_m.b + gp_succ_m.a / gp_succ_m.b by
            have ot : g'.s.get? m = some ⟨gp_m.a, gp_m.b + gp_succ_m.a / gp_succ_m.b⟩ :=
              squashSeq_nth_of_not_terminated mth_s_eq s_succ_mth_eq
            grind
          have m_lt_n : m < m.succ := Nat.lt_succ_self m
          refine ⟨(s_pos (Nat.lt_succ_of_lt m_lt_n) mth_s_eq).left, ?_⟩
          refine add_pos (s_pos (Nat.lt_succ_of_lt m_lt_n) mth_s_eq).right ?_
          have : 0 < gp_succ_m.a ∧ 0 < gp_succ_m.b := s_pos (lt_add_one <| m + 1) s_succ_mth_eq
          exact div_pos this.left this.right
        · -- the easy case: before the squashed position, nothing changes
          refine s_pos (Nat.lt_succ_of_lt <| Nat.lt_succ_of_lt succ_m_lt_n) ?_
          exact Eq.trans (squashGCF_nth_of_lt succ_m_lt_n).symm s_mth_eq'