-- Mathlib/SetTheory/Ordinal/Notation.lean
theorem fundamentalSequence_has_prop (o) : FundamentalSequenceProp o (fundamentalSequence o)

Proof state:
case oadd.inl.none.inr.zero.intro.intro
a : ONote
m : ℕ+
b : ONote
ihb : b = 0
e✝ : b.fundamentalSequence = Sum.inl none
f : ℕ → ONote
e : a.fundamentalSequence = Sum.inr f
e' : m.natPred = 0
h1 : a.repr.IsLimit
h2 : ∀ (i : ℕ), f i < f (i + 1) ∧ f i < a ∧ (a.NF → (f i).NF)
h3 : ∀ a_1 < a.repr, ∃ i, a_1 < (f i).repr
i : ℕ
⊢ (f i).repr < (f (i + 1)).repr ∧ (f i).repr < a.repr ∧ ((a.oadd 1 0).NF → ((f i).oadd 1 0).NF)

Tactic:
obtain ⟨h4, h5, h6⟩ := h2 i

Result:
case oadd.inl.none.inr.zero.intro.intro.intro.intro
a : ONote
m : ℕ+
b : ONote
ihb : b = 0
e✝ : b.fundamentalSequence = Sum.inl none
f : ℕ → ONote
e : a.fundamentalSequence = Sum.inr f
e' : m.natPred = 0
h1 : a.repr.IsLimit
h2 : ∀ (i : ℕ), f i < f (i + 1) ∧ f i < a ∧ (a.NF → (f i).NF)
h3 : ∀ a_1 < a.repr, ∃ i, a_1 < (f i).repr
i : ℕ
h4 : f i < f (i + 1)
h5 : f i < a
h6 : a.NF → (f i).NF
⊢ (f i).repr < (f (i + 1)).repr ∧ (f i).repr < a.repr ∧ ((a.oadd 1 0).NF → ((f i).oadd 1 0).NF)

Proof state:
case oadd.inl.some
a : ONote
m : ℕ+
b : ONote
iha : a.FundamentalSequenceProp a.fundamentalSequence
b' : ONote
ihb : b.repr = succ b'.repr ∧ (b.NF → b'.NF)
e : b.fundamentalSequence = Sum.inl (some b')
H : (a.oadd m b).NF
this : b.repr < ω ^ a.repr
⊢ b'.repr < ω ^ a.repr

Tactic:
rw [ihb.1] at this

Result:
case oadd.inl.some
a : ONote
m : ℕ+
b : ONote
iha : a.FundamentalSequenceProp a.fundamentalSequence
b' : ONote
ihb : b.repr = succ b'.repr ∧ (b.NF → b'.NF)
e : b.fundamentalSequence = Sum.inl (some b')
H : (a.oadd m b).NF
this : succ b'.repr < ω ^ a.repr
⊢ b'.repr < ω ^ a.repr

Proof state:
case oadd.inl.none.inr.succ
a : ONote
m : ℕ+
b : ONote
ihb : b = 0
e✝ : b.fundamentalSequence = Sum.inl none
f : ℕ → ONote
iha :
  a.repr.IsLimit ∧ (∀ (i : ℕ), f i < f (i + 1) ∧ f i < a ∧ (a.NF → (f i).NF)) ∧ ∀ a_1 < a.repr, ∃ i, a_1 < (f i).repr
e : a.fundamentalSequence = Sum.inr f
m' : ℕ
e' : m.natPred = m' + 1
⊢ (ω ^ a.repr * ↑m' + ω ^ a.repr + ω ^ a.repr).IsLimit ∧
    (∀ (i : ℕ),
        (f i).repr < (f (i + 1)).repr ∧
          (f i).repr < a.repr ∧ ((a.oadd (m' + 1).succPNat 0).NF → (a.oadd m'.succPNat ((f i).oadd 1 0)).NF)) ∧
      ∀ a_1 < ω ^ a.repr * ↑m' + ω ^ a.repr + ω ^ a.repr, ∃ i, a_1 < ω ^ a.repr * ↑m' + ω ^ a.repr + ω ^ (f i).repr

Tactic:
rcases iha with ⟨h1, h2, h3⟩

Result:
case oadd.inl.none.inr.succ.intro.intro
a : ONote
m : ℕ+
b : ONote
ihb : b = 0
e✝ : b.fundamentalSequence = Sum.inl none
f : ℕ → ONote
e : a.fundamentalSequence = Sum.inr f
m' : ℕ
e' : m.natPred = m' + 1
h1 : a.repr.IsLimit
h2 : ∀ (i : ℕ), f i < f (i + 1) ∧ f i < a ∧ (a.NF → (f i).NF)
h3 : ∀ a_1 < a.repr, ∃ i, a_1 < (f i).repr
⊢ (ω ^ a.repr * ↑m' + ω ^ a.repr + ω ^ a.repr).IsLimit ∧
    (∀ (i : ℕ),
        (f i).repr < (f (i + 1)).repr ∧
          (f i).repr < a.repr ∧ ((a.oadd (m' + 1).succPNat 0).NF → (a.oadd m'.succPNat ((f i).oadd 1 0)).NF)) ∧
      ∀ a_1 < ω ^ a.repr * ↑m' + ω ^ a.repr + ω ^ a.repr, ∃ i, a_1 < ω ^ a.repr * ↑m' + ω ^ a.repr + ω ^ (f i).repr

Proof state:
case oadd.inl.none.inl.some.zero
a : ONote
m : ℕ+
b : ONote
ihb : b = 0
e✝ : b.fundamentalSequence = Sum.inl none
a' : ONote
iha : a.repr = succ a'.repr ∧ (a.NF → a'.NF)
e : a.fundamentalSequence = Sum.inl (some a')
e' : m.natPred = 0
this : 0 < ω ^ a'.repr
⊢ (ω ^ a'.repr * ω).IsLimit ∧
    (∀ (i : ℕ),
        0 < ω ^ a'.repr ∧
          ω ^ a'.repr * ↑i + ω ^ a'.repr < ω ^ a'.repr * ω ∧ ((a.oadd 1 0).NF → (a'.oadd i.succPNat 0).NF)) ∧
      ∀ a < ω ^ a'.repr * ω, ∃ i, a < ω ^ a'.repr * ↑i + ω ^ a'.repr

Tactic:
refine
  ⟨isLimit_mul this isLimit_omega0, fun i =>
    ⟨this, ?_, fun H => @NF.oadd_zero _ _ (iha.2 H.fst)⟩, exists_lt_mul_omega0'⟩

Result:
case oadd.inl.none.inl.some.zero
a : ONote
m : ℕ+
b : ONote
ihb : b = 0
e✝ : b.fundamentalSequence = Sum.inl none
a' : ONote
iha : a.repr = succ a'.repr ∧ (a.NF → a'.NF)
e : a.fundamentalSequence = Sum.inl (some a')
e' : m.natPred = 0
this : 0 < ω ^ a'.repr
i : ℕ
⊢ ω ^ a'.repr * ↑i + ω ^ a'.repr < ω ^ a'.repr * ω

Proof state:
case oadd.inl.some
a : ONote
m : ℕ+
b : ONote
iha : a.FundamentalSequenceProp a.fundamentalSequence
b' : ONote
ihb : b.repr = succ b'.repr ∧ (b.NF → b'.NF)
e : b.fundamentalSequence = Sum.inl (some b')
H : (a.oadd m b).NF
this : succ b'.repr < ω ^ a.repr
⊢ b'.repr < ω ^ a.repr

Tactic:
exact (lt_succ _).trans this

Result:
no goals

Proof state:
case oadd.inr
a : ONote
m : ℕ+
b : ONote
iha : a.FundamentalSequenceProp a.fundamentalSequence
f : ℕ → ONote
ihb : b.repr.IsLimit ∧ (∀ (i : ℕ), f i < f (i + 1) ∧ f i < b ∧ (b.NF → (f i).NF)) ∧ ∀ a < b.repr, ∃ i, a < (f i).repr
e : b.fundamentalSequence = Sum.inr f
⊢ (a.oadd m b).repr.IsLimit ∧
    (∀ (i : ℕ),
        a.oadd m (f i) < a.oadd m (f (i + 1)) ∧ a.oadd m (f i) < a.oadd m b ∧ ((a.oadd m b).NF → (a.oadd m (f i)).NF)) ∧
      ∀ a_1 < (a.oadd m b).repr, ∃ i, a_1 < (a.oadd m (f i)).repr

Tactic:
rcases ihb with ⟨h1, h2, h3⟩

Result:
case oadd.inr.intro.intro
a : ONote
m : ℕ+
b : ONote
iha : a.FundamentalSequenceProp a.fundamentalSequence
f : ℕ → ONote
e : b.fundamentalSequence = Sum.inr f
h1 : b.repr.IsLimit
h2 : ∀ (i : ℕ), f i < f (i + 1) ∧ f i < b ∧ (b.NF → (f i).NF)
h3 : ∀ a < b.repr, ∃ i, a < (f i).repr
⊢ (a.oadd m b).repr.IsLimit ∧
    (∀ (i : ℕ),
        a.oadd m (f i) < a.oadd m (f (i + 1)) ∧ a.oadd m (f i) < a.oadd m b ∧ ((a.oadd m b).NF → (a.oadd m (f i)).NF)) ∧
      ∀ a_1 < (a.oadd m b).repr, ∃ i, a_1 < (a.oadd m (f i)).repr

Proof state:
case oadd.inl.none.inr.succ.intro.intro.intro.intro
a : ONote
m : ℕ+
b : ONote
ihb : b = 0
e✝ : b.fundamentalSequence = Sum.inl none
f : ℕ → ONote
e : a.fundamentalSequence = Sum.inr f
m' : ℕ
e' : m.natPred = m' + 1
h1 : a.repr.IsLimit
h2 : ∀ (i : ℕ), f i < f (i + 1) ∧ f i < a ∧ (a.NF → (f i).NF)
h3 : ∀ a_1 < a.repr, ∃ i, a_1 < (f i).repr
i : ℕ
h4 : f i < f (i + 1)
h5 : f i < a
h6 : a.NF → (f i).NF
⊢ (f i).repr < (f (i + 1)).repr ∧
    (f i).repr < a.repr ∧ ((a.oadd (m' + 1).succPNat 0).NF → (a.oadd m'.succPNat ((f i).oadd 1 0)).NF)

Tactic:
refine ⟨h4, h5, fun H => H.fst.oadd _ (NF.below_of_lt' ?_ (@NF.oadd_zero _ _ (h6 H.fst)))⟩

Result:
case oadd.inl.none.inr.succ.intro.intro.intro.intro
a : ONote
m : ℕ+
b : ONote
ihb : b = 0
e✝ : b.fundamentalSequence = Sum.inl none
f : ℕ → ONote
e : a.fundamentalSequence = Sum.inr f
m' : ℕ
e' : m.natPred = m' + 1
h1 : a.repr.IsLimit
h2 : ∀ (i : ℕ), f i < f (i + 1) ∧ f i < a ∧ (a.NF → (f i).NF)
h3 : ∀ a_1 < a.repr, ∃ i, a_1 < (f i).repr
i : ℕ
h4 : f i < f (i + 1)
h5 : f i < a
h6 : a.NF → (f i).NF
H : (a.oadd (m' + 1).succPNat 0).NF
⊢ ((f i).oadd 1 0).repr < ω ^ a.repr