l3lab/ntp-mathlib huggingface dataset:
theorem toZ_mono {i j : ι} (h_le : i ≤ j) : toZ i0 i ≤ toZ i0 j := by
  by_cases hi_max : IsMax i
  · rw [le_antisymm h_le (hi_max h_le)]
  by_cases hj_min : IsMin j
  · rw [le_antisymm h_le (hj_min h_le)]
  rcases le_or_lt i0 i with hi | hi <;> rcases le_or_lt i0 j with hj | hj
  · let m := Nat.find (exists_succ_iterate_of_le h_le)
    have hm : succ^[m] i = j := Nat.find_spec (exists_succ_iterate_of_le h_le)
    have hj_eq : j = succ^[(toZ i0 i).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_succ_toZ i hi]
      rw [Function.iterate_add]
      rfl
    by_contra h
    by_cases hm0 : m = 0
    · rw [hm0, Function.iterate_zero, id.def] at hm
      rw [hm] at h
      exact h (le_of_eq rfl)
    refine' hi_max (max_of_succ_le (le_trans _ (@le_of_toZ_le _ _ _ _ _ i0 j i _)))
    · have h_succ_le : succ^[(toZ i0 i).toNat + 1] i0 ≤ j := by
        rw [hj_eq]
        refine' Monotone.monotone_iterate_of_le_map succ_mono (le_succ i0) (add_le_add_left _ _)
        exact Nat.one_le_iff_ne_zero.mpr hm0
      rwa [Function.iterate_succ', Function.comp_apply, iterate_succ_toZ i hi] at h_succ_le
    · 

Proof state:
case neg.refine'_2
ι : Type u_1
inst✝³ : LinearOrder ι
inst✝² : SuccOrder ι
inst✝¹ : IsSuccArchimedean ι
inst✝ : PredOrder ι
i0 i✝ i j : ι
h_le : i ≤ j
hi_max : ¬IsMax i
hj_min : ¬IsMin j
hi : i0 ≤ i
hj : i0 ≤ j
m : ℕ := Nat.find (_ : ∃ n, succ^[n] i = j)
hm : succ^[m] i = j
hj_eq : j = succ^[Int.toNat (toZ i0 i) + m] i0
h : ¬toZ i0 i ≤ toZ i0 j
hm0 : ¬m = 0
⊢ toZ i0 j ≤ toZ i0 i

Next tactic:
exact le_of_not_le h
theorem toZ_mono {i j : ι} (h_le : i ≤ j) : toZ i0 i ≤ toZ i0 j := by
  by_cases hi_max : IsMax i
  · rw [le_antisymm h_le (hi_max h_le)]
  by_cases hj_min : IsMin j
  · rw [le_antisymm h_le (hj_min h_le)]
  rcases le_or_lt i0 i with hi | hi <;> rcases le_or_lt i0 j with hj | hj
  · let m := Nat.find (exists_succ_iterate_of_le h_le)
    have hm : succ^[m] i = j := Nat.find_spec (exists_succ_iterate_of_le h_le)
    have hj_eq : j = succ^[(toZ i0 i).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_succ_toZ i hi]
      rw [Function.iterate_add]
      rfl
    by_contra h
    by_cases hm0 : m = 0
    · rw [hm0, Function.iterate_zero, id.def] at hm
      rw [hm] at h
      exact h (le_of_eq rfl)
    refine' hi_max (max_of_succ_le (le_trans _ (@le_of_toZ_le _ _ _ _ _ i0 j i _)))
    · have h_succ_le : succ^[(toZ i0 i).toNat + 1] i0 ≤ j := by
        rw [hj_eq]
        refine' Monotone.monotone_iterate_of_le_map succ_mono (le_succ i0) (add_le_add_left _ _)
        exact Nat.one_le_iff_ne_zero.mpr hm0
      rwa [Function.iterate_succ', Function.comp_apply, iterate_succ_toZ i hi] at h_succ_le
    · exact le_of_not_le h
  · 

Proof state:
case neg.inl.inr
ι : Type u_1
inst✝³ : LinearOrder ι
inst✝² : SuccOrder ι
inst✝¹ : IsSuccArchimedean ι
inst✝ : PredOrder ι
i0 i✝ i j : ι
h_le : i ≤ j
hi_max : ¬IsMax i
hj_min : ¬IsMin j
hi : i0 ≤ i
hj : j < i0
⊢ toZ i0 i ≤ toZ i0 j

Next tactic:
exact absurd h_le (not_le.mpr (hj.trans_le hi))
theorem toZ_mono {i j : ι} (h_le : i ≤ j) : toZ i0 i ≤ toZ i0 j := by
  by_cases hi_max : IsMax i
  · rw [le_antisymm h_le (hi_max h_le)]
  by_cases hj_min : IsMin j
  · rw [le_antisymm h_le (hj_min h_le)]
  rcases le_or_lt i0 i with hi | hi <;> rcases le_or_lt i0 j with hj | hj
  · let m := Nat.find (exists_succ_iterate_of_le h_le)
    have hm : succ^[m] i = j := Nat.find_spec (exists_succ_iterate_of_le h_le)
    have hj_eq : j = succ^[(toZ i0 i).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_succ_toZ i hi]
      rw [Function.iterate_add]
      rfl
    by_contra h
    by_cases hm0 : m = 0
    · rw [hm0, Function.iterate_zero, id.def] at hm
      rw [hm] at h
      exact h (le_of_eq rfl)
    refine' hi_max (max_of_succ_le (le_trans _ (@le_of_toZ_le _ _ _ _ _ i0 j i _)))
    · have h_succ_le : succ^[(toZ i0 i).toNat + 1] i0 ≤ j := by
        rw [hj_eq]
        refine' Monotone.monotone_iterate_of_le_map succ_mono (le_succ i0) (add_le_add_left _ _)
        exact Nat.one_le_iff_ne_zero.mpr hm0
      rwa [Function.iterate_succ', Function.comp_apply, iterate_succ_toZ i hi] at h_succ_le
    · exact le_of_not_le h
  · exact absurd h_le (not_le.mpr (hj.trans_le hi))
  · 

Proof state:
case neg.inr.inl
ι : Type u_1
inst✝³ : LinearOrder ι
inst✝² : SuccOrder ι
inst✝¹ : IsSuccArchimedean ι
inst✝ : PredOrder ι
i0 i✝ i j : ι
h_le : i ≤ j
hi_max : ¬IsMax i
hj_min : ¬IsMin j
hi : i < i0
hj : i0 ≤ j
⊢ toZ i0 i ≤ toZ i0 j

Next tactic:
exact (toZ_neg hi).le.trans (toZ_nonneg hj)
theorem toZ_mono {i j : ι} (h_le : i ≤ j) : toZ i0 i ≤ toZ i0 j := by
  by_cases hi_max : IsMax i
  · rw [le_antisymm h_le (hi_max h_le)]
  by_cases hj_min : IsMin j
  · rw [le_antisymm h_le (hj_min h_le)]
  rcases le_or_lt i0 i with hi | hi <;> rcases le_or_lt i0 j with hj | hj
  · let m := Nat.find (exists_succ_iterate_of_le h_le)
    have hm : succ^[m] i = j := Nat.find_spec (exists_succ_iterate_of_le h_le)
    have hj_eq : j = succ^[(toZ i0 i).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_succ_toZ i hi]
      rw [Function.iterate_add]
      rfl
    by_contra h
    by_cases hm0 : m = 0
    · rw [hm0, Function.iterate_zero, id.def] at hm
      rw [hm] at h
      exact h (le_of_eq rfl)
    refine' hi_max (max_of_succ_le (le_trans _ (@le_of_toZ_le _ _ _ _ _ i0 j i _)))
    · have h_succ_le : succ^[(toZ i0 i).toNat + 1] i0 ≤ j := by
        rw [hj_eq]
        refine' Monotone.monotone_iterate_of_le_map succ_mono (le_succ i0) (add_le_add_left _ _)
        exact Nat.one_le_iff_ne_zero.mpr hm0
      rwa [Function.iterate_succ', Function.comp_apply, iterate_succ_toZ i hi] at h_succ_le
    · exact le_of_not_le h
  · exact absurd h_le (not_le.mpr (hj.trans_le hi))
  · exact (toZ_neg hi).le.trans (toZ_nonneg hj)
  · 

Proof state:
case neg.inr.inr
ι : Type u_1
inst✝³ : LinearOrder ι
inst✝² : SuccOrder ι
inst✝¹ : IsSuccArchimedean ι
inst✝ : PredOrder ι
i0 i✝ i j : ι
h_le : i ≤ j
hi_max : ¬IsMax i
hj_min : ¬IsMin j
hi : i < i0
hj : j < i0
⊢ toZ i0 i ≤ toZ i0 j

Next tactic:
let m := Nat.find (exists_pred_iterate_of_le h_le)
theorem toZ_mono {i j : ι} (h_le : i ≤ j) : toZ i0 i ≤ toZ i0 j := by
  by_cases hi_max : IsMax i
  · rw [le_antisymm h_le (hi_max h_le)]
  by_cases hj_min : IsMin j
  · rw [le_antisymm h_le (hj_min h_le)]
  rcases le_or_lt i0 i with hi | hi <;> rcases le_or_lt i0 j with hj | hj
  · let m := Nat.find (exists_succ_iterate_of_le h_le)
    have hm : succ^[m] i = j := Nat.find_spec (exists_succ_iterate_of_le h_le)
    have hj_eq : j = succ^[(toZ i0 i).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_succ_toZ i hi]
      rw [Function.iterate_add]
      rfl
    by_contra h
    by_cases hm0 : m = 0
    · rw [hm0, Function.iterate_zero, id.def] at hm
      rw [hm] at h
      exact h (le_of_eq rfl)
    refine' hi_max (max_of_succ_le (le_trans _ (@le_of_toZ_le _ _ _ _ _ i0 j i _)))
    · have h_succ_le : succ^[(toZ i0 i).toNat + 1] i0 ≤ j := by
        rw [hj_eq]
        refine' Monotone.monotone_iterate_of_le_map succ_mono (le_succ i0) (add_le_add_left _ _)
        exact Nat.one_le_iff_ne_zero.mpr hm0
      rwa [Function.iterate_succ', Function.comp_apply, iterate_succ_toZ i hi] at h_succ_le
    · exact le_of_not_le h
  · exact absurd h_le (not_le.mpr (hj.trans_le hi))
  · exact (toZ_neg hi).le.trans (toZ_nonneg hj)
  · let m := Nat.find (exists_pred_iterate_of_le h_le)
    

Proof state:
case neg.inr.inr
ι : Type u_1
inst✝³ : LinearOrder ι
inst✝² : SuccOrder ι
inst✝¹ : IsSuccArchimedean ι
inst✝ : PredOrder ι
i0 i✝ i j : ι
h_le : i ≤ j
hi_max : ¬IsMax i
hj_min : ¬IsMin j
hi : i < i0
hj : j < i0
m : ℕ := Nat.find (_ : ∃ n, pred^[n] j = i)
⊢ toZ i0 i ≤ toZ i0 j

Next tactic:
have hm : pred^[m] j = i := Nat.find_spec (exists_pred_iterate_of_le h_le)
theorem toZ_mono {i j : ι} (h_le : i ≤ j) : toZ i0 i ≤ toZ i0 j := by
  by_cases hi_max : IsMax i
  · rw [le_antisymm h_le (hi_max h_le)]
  by_cases hj_min : IsMin j
  · rw [le_antisymm h_le (hj_min h_le)]
  rcases le_or_lt i0 i with hi | hi <;> rcases le_or_lt i0 j with hj | hj
  · let m := Nat.find (exists_succ_iterate_of_le h_le)
    have hm : succ^[m] i = j := Nat.find_spec (exists_succ_iterate_of_le h_le)
    have hj_eq : j = succ^[(toZ i0 i).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_succ_toZ i hi]
      rw [Function.iterate_add]
      rfl
    by_contra h
    by_cases hm0 : m = 0
    · rw [hm0, Function.iterate_zero, id.def] at hm
      rw [hm] at h
      exact h (le_of_eq rfl)
    refine' hi_max (max_of_succ_le (le_trans _ (@le_of_toZ_le _ _ _ _ _ i0 j i _)))
    · have h_succ_le : succ^[(toZ i0 i).toNat + 1] i0 ≤ j := by
        rw [hj_eq]
        refine' Monotone.monotone_iterate_of_le_map succ_mono (le_succ i0) (add_le_add_left _ _)
        exact Nat.one_le_iff_ne_zero.mpr hm0
      rwa [Function.iterate_succ', Function.comp_apply, iterate_succ_toZ i hi] at h_succ_le
    · exact le_of_not_le h
  · exact absurd h_le (not_le.mpr (hj.trans_le hi))
  · exact (toZ_neg hi).le.trans (toZ_nonneg hj)
  · let m := Nat.find (exists_pred_iterate_of_le h_le)
    have hm : pred^[m] j = i := Nat.find_spec (exists_pred_iterate_of_le h_le)
    

Proof state:
case neg.inr.inr
ι : Type u_1
inst✝³ : LinearOrder ι
inst✝² : SuccOrder ι
inst✝¹ : IsSuccArchimedean ι
inst✝ : PredOrder ι
i0 i✝ i j : ι
h_le : i ≤ j
hi_max : ¬IsMax i
hj_min : ¬IsMin j
hi : i < i0
hj : j < i0
m : ℕ := Nat.find (_ : ∃ n, pred^[n] j = i)
hm : pred^[m] j = i
⊢ toZ i0 i ≤ toZ i0 j

Next tactic:
have hj_eq : i = pred^[(-toZ i0 j).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_pred_toZ j hj]
      rw [Function.iterate_add]
      rfl
theorem toZ_mono {i j : ι} (h_le : i ≤ j) : toZ i0 i ≤ toZ i0 j := by
  by_cases hi_max : IsMax i
  · rw [le_antisymm h_le (hi_max h_le)]
  by_cases hj_min : IsMin j
  · rw [le_antisymm h_le (hj_min h_le)]
  rcases le_or_lt i0 i with hi | hi <;> rcases le_or_lt i0 j with hj | hj
  · let m := Nat.find (exists_succ_iterate_of_le h_le)
    have hm : succ^[m] i = j := Nat.find_spec (exists_succ_iterate_of_le h_le)
    have hj_eq : j = succ^[(toZ i0 i).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_succ_toZ i hi]
      rw [Function.iterate_add]
      rfl
    by_contra h
    by_cases hm0 : m = 0
    · rw [hm0, Function.iterate_zero, id.def] at hm
      rw [hm] at h
      exact h (le_of_eq rfl)
    refine' hi_max (max_of_succ_le (le_trans _ (@le_of_toZ_le _ _ _ _ _ i0 j i _)))
    · have h_succ_le : succ^[(toZ i0 i).toNat + 1] i0 ≤ j := by
        rw [hj_eq]
        refine' Monotone.monotone_iterate_of_le_map succ_mono (le_succ i0) (add_le_add_left _ _)
        exact Nat.one_le_iff_ne_zero.mpr hm0
      rwa [Function.iterate_succ', Function.comp_apply, iterate_succ_toZ i hi] at h_succ_le
    · exact le_of_not_le h
  · exact absurd h_le (not_le.mpr (hj.trans_le hi))
  · exact (toZ_neg hi).le.trans (toZ_nonneg hj)
  · let m := Nat.find (exists_pred_iterate_of_le h_le)
    have hm : pred^[m] j = i := Nat.find_spec (exists_pred_iterate_of_le h_le)
    have hj_eq : i = pred^[(-toZ i0 j).toNat + m] i0 := by
      

Proof state:
ι : Type u_1
inst✝³ : LinearOrder ι
inst✝² : SuccOrder ι
inst✝¹ : IsSuccArchimedean ι
inst✝ : PredOrder ι
i0 i✝ i j : ι
h_le : i ≤ j
hi_max : ¬IsMax i
hj_min : ¬IsMin j
hi : i < i0
hj : j < i0
m : ℕ := Nat.find (_ : ∃ n, pred^[n] j = i)
hm : pred^[m] j = i
⊢ i = pred^[Int.toNat (-toZ i0 j) + m] i0

Next tactic:
rw [← hm, add_comm]
theorem toZ_mono {i j : ι} (h_le : i ≤ j) : toZ i0 i ≤ toZ i0 j := by
  by_cases hi_max : IsMax i
  · rw [le_antisymm h_le (hi_max h_le)]
  by_cases hj_min : IsMin j
  · rw [le_antisymm h_le (hj_min h_le)]
  rcases le_or_lt i0 i with hi | hi <;> rcases le_or_lt i0 j with hj | hj
  · let m := Nat.find (exists_succ_iterate_of_le h_le)
    have hm : succ^[m] i = j := Nat.find_spec (exists_succ_iterate_of_le h_le)
    have hj_eq : j = succ^[(toZ i0 i).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_succ_toZ i hi]
      rw [Function.iterate_add]
      rfl
    by_contra h
    by_cases hm0 : m = 0
    · rw [hm0, Function.iterate_zero, id.def] at hm
      rw [hm] at h
      exact h (le_of_eq rfl)
    refine' hi_max (max_of_succ_le (le_trans _ (@le_of_toZ_le _ _ _ _ _ i0 j i _)))
    · have h_succ_le : succ^[(toZ i0 i).toNat + 1] i0 ≤ j := by
        rw [hj_eq]
        refine' Monotone.monotone_iterate_of_le_map succ_mono (le_succ i0) (add_le_add_left _ _)
        exact Nat.one_le_iff_ne_zero.mpr hm0
      rwa [Function.iterate_succ', Function.comp_apply, iterate_succ_toZ i hi] at h_succ_le
    · exact le_of_not_le h
  · exact absurd h_le (not_le.mpr (hj.trans_le hi))
  · exact (toZ_neg hi).le.trans (toZ_nonneg hj)
  · let m := Nat.find (exists_pred_iterate_of_le h_le)
    have hm : pred^[m] j = i := Nat.find_spec (exists_pred_iterate_of_le h_le)
    have hj_eq : i = pred^[(-toZ i0 j).toNat + m] i0 := by
      rw [← hm, add_comm]
      

Proof state:
ι : Type u_1
inst✝³ : LinearOrder ι
inst✝² : SuccOrder ι
inst✝¹ : IsSuccArchimedean ι
inst✝ : PredOrder ι
i0 i✝ i j : ι
h_le : i ≤ j
hi_max : ¬IsMax i
hj_min : ¬IsMin j
hi : i < i0
hj : j < i0
m : ℕ := Nat.find (_ : ∃ n, pred^[n] j = i)
hm : pred^[m] j = i
⊢ pred^[m] j = pred^[m + Int.toNat (-toZ i0 j)] i0

Next tactic:
nth_rw 1 [← iterate_pred_toZ j hj]
theorem toZ_mono {i j : ι} (h_le : i ≤ j) : toZ i0 i ≤ toZ i0 j := by
  by_cases hi_max : IsMax i
  · rw [le_antisymm h_le (hi_max h_le)]
  by_cases hj_min : IsMin j
  · rw [le_antisymm h_le (hj_min h_le)]
  rcases le_or_lt i0 i with hi | hi <;> rcases le_or_lt i0 j with hj | hj
  · let m := Nat.find (exists_succ_iterate_of_le h_le)
    have hm : succ^[m] i = j := Nat.find_spec (exists_succ_iterate_of_le h_le)
    have hj_eq : j = succ^[(toZ i0 i).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_succ_toZ i hi]
      rw [Function.iterate_add]
      rfl
    by_contra h
    by_cases hm0 : m = 0
    · rw [hm0, Function.iterate_zero, id.def] at hm
      rw [hm] at h
      exact h (le_of_eq rfl)
    refine' hi_max (max_of_succ_le (le_trans _ (@le_of_toZ_le _ _ _ _ _ i0 j i _)))
    · have h_succ_le : succ^[(toZ i0 i).toNat + 1] i0 ≤ j := by
        rw [hj_eq]
        refine' Monotone.monotone_iterate_of_le_map succ_mono (le_succ i0) (add_le_add_left _ _)
        exact Nat.one_le_iff_ne_zero.mpr hm0
      rwa [Function.iterate_succ', Function.comp_apply, iterate_succ_toZ i hi] at h_succ_le
    · exact le_of_not_le h
  · exact absurd h_le (not_le.mpr (hj.trans_le hi))
  · exact (toZ_neg hi).le.trans (toZ_nonneg hj)
  · let m := Nat.find (exists_pred_iterate_of_le h_le)
    have hm : pred^[m] j = i := Nat.find_spec (exists_pred_iterate_of_le h_le)
    have hj_eq : i = pred^[(-toZ i0 j).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_pred_toZ j hj]
      

Proof state:
ι : Type u_1
inst✝³ : LinearOrder ι
inst✝² : SuccOrder ι
inst✝¹ : IsSuccArchimedean ι
inst✝ : PredOrder ι
i0 i✝ i j : ι
h_le : i ≤ j
hi_max : ¬IsMax i
hj_min : ¬IsMin j
hi : i < i0
hj : j < i0
m : ℕ := Nat.find (_ : ∃ n, pred^[n] j = i)
hm : pred^[m] j = i
⊢ pred^[m] (pred^[Int.toNat (-toZ i0 j)] i0) = pred^[m + Int.toNat (-toZ i0 j)] i0

Next tactic:
rw [Function.iterate_add]
theorem toZ_mono {i j : ι} (h_le : i ≤ j) : toZ i0 i ≤ toZ i0 j := by
  by_cases hi_max : IsMax i
  · rw [le_antisymm h_le (hi_max h_le)]
  by_cases hj_min : IsMin j
  · rw [le_antisymm h_le (hj_min h_le)]
  rcases le_or_lt i0 i with hi | hi <;> rcases le_or_lt i0 j with hj | hj
  · let m := Nat.find (exists_succ_iterate_of_le h_le)
    have hm : succ^[m] i = j := Nat.find_spec (exists_succ_iterate_of_le h_le)
    have hj_eq : j = succ^[(toZ i0 i).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_succ_toZ i hi]
      rw [Function.iterate_add]
      rfl
    by_contra h
    by_cases hm0 : m = 0
    · rw [hm0, Function.iterate_zero, id.def] at hm
      rw [hm] at h
      exact h (le_of_eq rfl)
    refine' hi_max (max_of_succ_le (le_trans _ (@le_of_toZ_le _ _ _ _ _ i0 j i _)))
    · have h_succ_le : succ^[(toZ i0 i).toNat + 1] i0 ≤ j := by
        rw [hj_eq]
        refine' Monotone.monotone_iterate_of_le_map succ_mono (le_succ i0) (add_le_add_left _ _)
        exact Nat.one_le_iff_ne_zero.mpr hm0
      rwa [Function.iterate_succ', Function.comp_apply, iterate_succ_toZ i hi] at h_succ_le
    · exact le_of_not_le h
  · exact absurd h_le (not_le.mpr (hj.trans_le hi))
  · exact (toZ_neg hi).le.trans (toZ_nonneg hj)
  · let m := Nat.find (exists_pred_iterate_of_le h_le)
    have hm : pred^[m] j = i := Nat.find_spec (exists_pred_iterate_of_le h_le)
    have hj_eq : i = pred^[(-toZ i0 j).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_pred_toZ j hj]
      rw [Function.iterate_add]
      

Proof state:
ι : Type u_1
inst✝³ : LinearOrder ι
inst✝² : SuccOrder ι
inst✝¹ : IsSuccArchimedean ι
inst✝ : PredOrder ι
i0 i✝ i j : ι
h_le : i ≤ j
hi_max : ¬IsMax i
hj_min : ¬IsMin j
hi : i < i0
hj : j < i0
m : ℕ := Nat.find (_ : ∃ n, pred^[n] j = i)
hm : pred^[m] j = i
⊢ pred^[m] (pred^[Int.toNat (-toZ i0 j)] i0) = (pred^[m] ∘ pred^[Int.toNat (-toZ i0 j)]) i0

Next tactic:
rfl
theorem toZ_mono {i j : ι} (h_le : i ≤ j) : toZ i0 i ≤ toZ i0 j := by
  by_cases hi_max : IsMax i
  · rw [le_antisymm h_le (hi_max h_le)]
  by_cases hj_min : IsMin j
  · rw [le_antisymm h_le (hj_min h_le)]
  rcases le_or_lt i0 i with hi | hi <;> rcases le_or_lt i0 j with hj | hj
  · let m := Nat.find (exists_succ_iterate_of_le h_le)
    have hm : succ^[m] i = j := Nat.find_spec (exists_succ_iterate_of_le h_le)
    have hj_eq : j = succ^[(toZ i0 i).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_succ_toZ i hi]
      rw [Function.iterate_add]
      rfl
    by_contra h
    by_cases hm0 : m = 0
    · rw [hm0, Function.iterate_zero, id.def] at hm
      rw [hm] at h
      exact h (le_of_eq rfl)
    refine' hi_max (max_of_succ_le (le_trans _ (@le_of_toZ_le _ _ _ _ _ i0 j i _)))
    · have h_succ_le : succ^[(toZ i0 i).toNat + 1] i0 ≤ j := by
        rw [hj_eq]
        refine' Monotone.monotone_iterate_of_le_map succ_mono (le_succ i0) (add_le_add_left _ _)
        exact Nat.one_le_iff_ne_zero.mpr hm0
      rwa [Function.iterate_succ', Function.comp_apply, iterate_succ_toZ i hi] at h_succ_le
    · exact le_of_not_le h
  · exact absurd h_le (not_le.mpr (hj.trans_le hi))
  · exact (toZ_neg hi).le.trans (toZ_nonneg hj)
  · let m := Nat.find (exists_pred_iterate_of_le h_le)
    have hm : pred^[m] j = i := Nat.find_spec (exists_pred_iterate_of_le h_le)
    have hj_eq : i = pred^[(-toZ i0 j).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_pred_toZ j hj]
      rw [Function.iterate_add]
      rfl
    

Proof state:
case neg.inr.inr
ι : Type u_1
inst✝³ : LinearOrder ι
inst✝² : SuccOrder ι
inst✝¹ : IsSuccArchimedean ι
inst✝ : PredOrder ι
i0 i✝ i j : ι
h_le : i ≤ j
hi_max : ¬IsMax i
hj_min : ¬IsMin j
hi : i < i0
hj : j < i0
m : ℕ := Nat.find (_ : ∃ n, pred^[n] j = i)
hm : pred^[m] j = i
hj_eq : i = pred^[Int.toNat (-toZ i0 j) + m] i0
⊢ toZ i0 i ≤ toZ i0 j

Next tactic:
by_contra h
theorem toZ_mono {i j : ι} (h_le : i ≤ j) : toZ i0 i ≤ toZ i0 j := by
  by_cases hi_max : IsMax i
  · rw [le_antisymm h_le (hi_max h_le)]
  by_cases hj_min : IsMin j
  · rw [le_antisymm h_le (hj_min h_le)]
  rcases le_or_lt i0 i with hi | hi <;> rcases le_or_lt i0 j with hj | hj
  · let m := Nat.find (exists_succ_iterate_of_le h_le)
    have hm : succ^[m] i = j := Nat.find_spec (exists_succ_iterate_of_le h_le)
    have hj_eq : j = succ^[(toZ i0 i).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_succ_toZ i hi]
      rw [Function.iterate_add]
      rfl
    by_contra h
    by_cases hm0 : m = 0
    · rw [hm0, Function.iterate_zero, id.def] at hm
      rw [hm] at h
      exact h (le_of_eq rfl)
    refine' hi_max (max_of_succ_le (le_trans _ (@le_of_toZ_le _ _ _ _ _ i0 j i _)))
    · have h_succ_le : succ^[(toZ i0 i).toNat + 1] i0 ≤ j := by
        rw [hj_eq]
        refine' Monotone.monotone_iterate_of_le_map succ_mono (le_succ i0) (add_le_add_left _ _)
        exact Nat.one_le_iff_ne_zero.mpr hm0
      rwa [Function.iterate_succ', Function.comp_apply, iterate_succ_toZ i hi] at h_succ_le
    · exact le_of_not_le h
  · exact absurd h_le (not_le.mpr (hj.trans_le hi))
  · exact (toZ_neg hi).le.trans (toZ_nonneg hj)
  · let m := Nat.find (exists_pred_iterate_of_le h_le)
    have hm : pred^[m] j = i := Nat.find_spec (exists_pred_iterate_of_le h_le)
    have hj_eq : i = pred^[(-toZ i0 j).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_pred_toZ j hj]
      rw [Function.iterate_add]
      rfl
    by_contra h
    

Proof state:
case neg.inr.inr
ι : Type u_1
inst✝³ : LinearOrder ι
inst✝² : SuccOrder ι
inst✝¹ : IsSuccArchimedean ι
inst✝ : PredOrder ι
i0 i✝ i j : ι
h_le : i ≤ j
hi_max : ¬IsMax i
hj_min : ¬IsMin j
hi : i < i0
hj : j < i0
m : ℕ := Nat.find (_ : ∃ n, pred^[n] j = i)
hm : pred^[m] j = i
hj_eq : i = pred^[Int.toNat (-toZ i0 j) + m] i0
h : ¬toZ i0 i ≤ toZ i0 j
⊢ False

Next tactic:
by_cases hm0 : m = 0
theorem toZ_mono {i j : ι} (h_le : i ≤ j) : toZ i0 i ≤ toZ i0 j := by
  by_cases hi_max : IsMax i
  · rw [le_antisymm h_le (hi_max h_le)]
  by_cases hj_min : IsMin j
  · rw [le_antisymm h_le (hj_min h_le)]
  rcases le_or_lt i0 i with hi | hi <;> rcases le_or_lt i0 j with hj | hj
  · let m := Nat.find (exists_succ_iterate_of_le h_le)
    have hm : succ^[m] i = j := Nat.find_spec (exists_succ_iterate_of_le h_le)
    have hj_eq : j = succ^[(toZ i0 i).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_succ_toZ i hi]
      rw [Function.iterate_add]
      rfl
    by_contra h
    by_cases hm0 : m = 0
    · rw [hm0, Function.iterate_zero, id.def] at hm
      rw [hm] at h
      exact h (le_of_eq rfl)
    refine' hi_max (max_of_succ_le (le_trans _ (@le_of_toZ_le _ _ _ _ _ i0 j i _)))
    · have h_succ_le : succ^[(toZ i0 i).toNat + 1] i0 ≤ j := by
        rw [hj_eq]
        refine' Monotone.monotone_iterate_of_le_map succ_mono (le_succ i0) (add_le_add_left _ _)
        exact Nat.one_le_iff_ne_zero.mpr hm0
      rwa [Function.iterate_succ', Function.comp_apply, iterate_succ_toZ i hi] at h_succ_le
    · exact le_of_not_le h
  · exact absurd h_le (not_le.mpr (hj.trans_le hi))
  · exact (toZ_neg hi).le.trans (toZ_nonneg hj)
  · let m := Nat.find (exists_pred_iterate_of_le h_le)
    have hm : pred^[m] j = i := Nat.find_spec (exists_pred_iterate_of_le h_le)
    have hj_eq : i = pred^[(-toZ i0 j).toNat + m] i0 := by
      rw [← hm, add_comm]
      nth_rw 1 [← iterate_pred_toZ j hj]
      rw [Function.iterate_add]
      rfl
    by_contra h
    by_cases hm0 : m = 0
    · 

Proof state:
case pos
ι : Type u_1
inst✝³ : LinearOrder ι
inst✝² : SuccOrder ι
inst✝¹ : IsSuccArchimedean ι
inst✝ : PredOrder ι
i0 i✝ i j : ι
h_le : i ≤ j
hi_max : ¬IsMax i
hj_min : ¬IsMin j
hi : i < i0
hj : j < i0
m : ℕ := Nat.find (_ : ∃ n, pred^[n] j = i)
hm : pred^[m] j = i
hj_eq : i = pred^[Int.toNat (-toZ i0 j) + m] i0
h : ¬toZ i0 i ≤ toZ i0 j
hm0 : m = 0
⊢ False

Next tactic:
rw [hm0, Function.iterate_zero, id.def] at hm