l3lab/ntp-mathlib huggingface dataset:
theorem mem_sumLift₂ :
    c ∈ sumLift₂ f g a b ↔
      (∃ a₁ b₁ c₁, a = inl a₁ ∧ b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
        ∃ a₂ b₂ c₂, a = inr a₂ ∧ b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g a₂ b₂ := by
  constructor
  · cases' a with a a <;> cases' b with b b
    · rw [sumLift₂, mem_map]
      rintro ⟨c, hc, rfl⟩
      

Proof state:
case mp.inl.inl.intro.intro
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁
b : β₁
c : γ₁
hc : c ∈ f a b
⊢ (∃ a₁ b₁ c₁, inl a = inl a₁ ∧ inl b = inl b₁ ∧ Embedding.inl c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
    ∃ a₂ b₂ c₂, inl a = inr a₂ ∧ inl b = inr b₂ ∧ Embedding.inl c = inr c₂ ∧ c₂ ∈ g a₂ b₂

Next tactic:
exact Or.inl ⟨a, b, c, rfl, rfl, rfl, hc⟩
theorem mem_sumLift₂ :
    c ∈ sumLift₂ f g a b ↔
      (∃ a₁ b₁ c₁, a = inl a₁ ∧ b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
        ∃ a₂ b₂ c₂, a = inr a₂ ∧ b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g a₂ b₂ := by
  constructor
  · cases' a with a a <;> cases' b with b b
    · rw [sumLift₂, mem_map]
      rintro ⟨c, hc, rfl⟩
      exact Or.inl ⟨a, b, c, rfl, rfl, rfl, hc⟩
    · 

Proof state:
case mp.inl.inr
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
c : γ₁ ⊕ γ₂
a : α₁
b : β₂
⊢ c ∈ sumLift₂ f g (inl a) (inr b) →
    (∃ a₁ b₁ c₁, inl a = inl a₁ ∧ inr b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
      ∃ a₂ b₂ c₂, inl a = inr a₂ ∧ inr b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g a₂ b₂

Next tactic:
refine' fun h ↦ (not_mem_empty _ h).elim
theorem mem_sumLift₂ :
    c ∈ sumLift₂ f g a b ↔
      (∃ a₁ b₁ c₁, a = inl a₁ ∧ b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
        ∃ a₂ b₂ c₂, a = inr a₂ ∧ b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g a₂ b₂ := by
  constructor
  · cases' a with a a <;> cases' b with b b
    · rw [sumLift₂, mem_map]
      rintro ⟨c, hc, rfl⟩
      exact Or.inl ⟨a, b, c, rfl, rfl, rfl, hc⟩
    · refine' fun h ↦ (not_mem_empty _ h).elim
    · 

Proof state:
case mp.inr.inl
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
c : γ₁ ⊕ γ₂
a : α₂
b : β₁
⊢ c ∈ sumLift₂ f g (inr a) (inl b) →
    (∃ a₁ b₁ c₁, inr a = inl a₁ ∧ inl b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
      ∃ a₂ b₂ c₂, inr a = inr a₂ ∧ inl b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g a₂ b₂

Next tactic:
refine' fun h ↦ (not_mem_empty _ h).elim
theorem mem_sumLift₂ :
    c ∈ sumLift₂ f g a b ↔
      (∃ a₁ b₁ c₁, a = inl a₁ ∧ b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
        ∃ a₂ b₂ c₂, a = inr a₂ ∧ b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g a₂ b₂ := by
  constructor
  · cases' a with a a <;> cases' b with b b
    · rw [sumLift₂, mem_map]
      rintro ⟨c, hc, rfl⟩
      exact Or.inl ⟨a, b, c, rfl, rfl, rfl, hc⟩
    · refine' fun h ↦ (not_mem_empty _ h).elim
    · refine' fun h ↦ (not_mem_empty _ h).elim
    · 

Proof state:
case mp.inr.inr
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
c : γ₁ ⊕ γ₂
a : α₂
b : β₂
⊢ c ∈ sumLift₂ f g (inr a) (inr b) →
    (∃ a₁ b₁ c₁, inr a = inl a₁ ∧ inr b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
      ∃ a₂ b₂ c₂, inr a = inr a₂ ∧ inr b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g a₂ b₂

Next tactic:
rw [sumLift₂, mem_map]
theorem mem_sumLift₂ :
    c ∈ sumLift₂ f g a b ↔
      (∃ a₁ b₁ c₁, a = inl a₁ ∧ b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
        ∃ a₂ b₂ c₂, a = inr a₂ ∧ b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g a₂ b₂ := by
  constructor
  · cases' a with a a <;> cases' b with b b
    · rw [sumLift₂, mem_map]
      rintro ⟨c, hc, rfl⟩
      exact Or.inl ⟨a, b, c, rfl, rfl, rfl, hc⟩
    · refine' fun h ↦ (not_mem_empty _ h).elim
    · refine' fun h ↦ (not_mem_empty _ h).elim
    · rw [sumLift₂, mem_map]
      

Proof state:
case mp.inr.inr
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
c : γ₁ ⊕ γ₂
a : α₂
b : β₂
⊢ (∃ a_1 ∈ g a b, Embedding.inr a_1 = c) →
    (∃ a₁ b₁ c₁, inr a = inl a₁ ∧ inr b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
      ∃ a₂ b₂ c₂, inr a = inr a₂ ∧ inr b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g a₂ b₂

Next tactic:
rintro ⟨c, hc, rfl⟩
theorem mem_sumLift₂ :
    c ∈ sumLift₂ f g a b ↔
      (∃ a₁ b₁ c₁, a = inl a₁ ∧ b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
        ∃ a₂ b₂ c₂, a = inr a₂ ∧ b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g a₂ b₂ := by
  constructor
  · cases' a with a a <;> cases' b with b b
    · rw [sumLift₂, mem_map]
      rintro ⟨c, hc, rfl⟩
      exact Or.inl ⟨a, b, c, rfl, rfl, rfl, hc⟩
    · refine' fun h ↦ (not_mem_empty _ h).elim
    · refine' fun h ↦ (not_mem_empty _ h).elim
    · rw [sumLift₂, mem_map]
      rintro ⟨c, hc, rfl⟩
      

Proof state:
case mp.inr.inr.intro.intro
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₂
b : β₂
c : γ₂
hc : c ∈ g a b
⊢ (∃ a₁ b₁ c₁, inr a = inl a₁ ∧ inr b = inl b₁ ∧ Embedding.inr c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
    ∃ a₂ b₂ c₂, inr a = inr a₂ ∧ inr b = inr b₂ ∧ Embedding.inr c = inr c₂ ∧ c₂ ∈ g a₂ b₂

Next tactic:
exact Or.inr ⟨a, b, c, rfl, rfl, rfl, hc⟩
theorem mem_sumLift₂ :
    c ∈ sumLift₂ f g a b ↔
      (∃ a₁ b₁ c₁, a = inl a₁ ∧ b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
        ∃ a₂ b₂ c₂, a = inr a₂ ∧ b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g a₂ b₂ := by
  constructor
  · cases' a with a a <;> cases' b with b b
    · rw [sumLift₂, mem_map]
      rintro ⟨c, hc, rfl⟩
      exact Or.inl ⟨a, b, c, rfl, rfl, rfl, hc⟩
    · refine' fun h ↦ (not_mem_empty _ h).elim
    · refine' fun h ↦ (not_mem_empty _ h).elim
    · rw [sumLift₂, mem_map]
      rintro ⟨c, hc, rfl⟩
      exact Or.inr ⟨a, b, c, rfl, rfl, rfl, hc⟩
  · 

Proof state:
case mpr
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
⊢ ((∃ a₁ b₁ c₁, a = inl a₁ ∧ b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
      ∃ a₂ b₂ c₂, a = inr a₂ ∧ b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g a₂ b₂) →
    c ∈ sumLift₂ f g a b

Next tactic:
rintro (⟨a, b, c, rfl, rfl, rfl, h⟩ | ⟨a, b, c, rfl, rfl, rfl, h⟩)
theorem mem_sumLift₂ :
    c ∈ sumLift₂ f g a b ↔
      (∃ a₁ b₁ c₁, a = inl a₁ ∧ b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
        ∃ a₂ b₂ c₂, a = inr a₂ ∧ b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g a₂ b₂ := by
  constructor
  · cases' a with a a <;> cases' b with b b
    · rw [sumLift₂, mem_map]
      rintro ⟨c, hc, rfl⟩
      exact Or.inl ⟨a, b, c, rfl, rfl, rfl, hc⟩
    · refine' fun h ↦ (not_mem_empty _ h).elim
    · refine' fun h ↦ (not_mem_empty _ h).elim
    · rw [sumLift₂, mem_map]
      rintro ⟨c, hc, rfl⟩
      exact Or.inr ⟨a, b, c, rfl, rfl, rfl, hc⟩
  · rintro (⟨a, b, c, rfl, rfl, rfl, h⟩ | ⟨a, b, c, rfl, rfl, rfl, h⟩) <;> 

Proof state:
case mpr.inl.intro.intro.intro.intro.intro.intro
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁
b : β₁
c : γ₁
h : c ∈ f a b
⊢ inl c ∈ sumLift₂ f g (inl a) (inl b)

Next tactic:
exact mem_map_of_mem _ h
theorem mem_sumLift₂ :
    c ∈ sumLift₂ f g a b ↔
      (∃ a₁ b₁ c₁, a = inl a₁ ∧ b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f a₁ b₁) ∨
        ∃ a₂ b₂ c₂, a = inr a₂ ∧ b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g a₂ b₂ := by
  constructor
  · cases' a with a a <;> cases' b with b b
    · rw [sumLift₂, mem_map]
      rintro ⟨c, hc, rfl⟩
      exact Or.inl ⟨a, b, c, rfl, rfl, rfl, hc⟩
    · refine' fun h ↦ (not_mem_empty _ h).elim
    · refine' fun h ↦ (not_mem_empty _ h).elim
    · rw [sumLift₂, mem_map]
      rintro ⟨c, hc, rfl⟩
      exact Or.inr ⟨a, b, c, rfl, rfl, rfl, hc⟩
  · rintro (⟨a, b, c, rfl, rfl, rfl, h⟩ | ⟨a, b, c, rfl, rfl, rfl, h⟩) <;> 

Proof state:
case mpr.inr.intro.intro.intro.intro.intro.intro
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₂
b : β₂
c : γ₂
h : c ∈ g a b
⊢ inr c ∈ sumLift₂ f g (inr a) (inr b)

Next tactic:
exact mem_map_of_mem _ h
theorem inl_mem_sumLift₂ {c₁ : γ₁} :
    inl c₁ ∈ sumLift₂ f g a b ↔ ∃ a₁ b₁, a = inl a₁ ∧ b = inl b₁ ∧ c₁ ∈ f a₁ b₁ := by
  

Proof state:
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
c₁ : γ₁
⊢ inl c₁ ∈ sumLift₂ f g a b ↔ ∃ a₁ b₁, a = inl a₁ ∧ b = inl b₁ ∧ c₁ ∈ f a₁ b₁

Next tactic:
rw [mem_sumLift₂, or_iff_left]
theorem inl_mem_sumLift₂ {c₁ : γ₁} :
    inl c₁ ∈ sumLift₂ f g a b ↔ ∃ a₁ b₁, a = inl a₁ ∧ b = inl b₁ ∧ c₁ ∈ f a₁ b₁ := by
  rw [mem_sumLift₂, or_iff_left]
  

Proof state:
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
c₁ : γ₁
⊢ (∃ a₁ b₁ c₁_1, a = inl a₁ ∧ b = inl b₁ ∧ inl c₁ = inl c₁_1 ∧ c₁_1 ∈ f a₁ b₁) ↔
    ∃ a₁ b₁, a = inl a₁ ∧ b = inl b₁ ∧ c₁ ∈ f a₁ b₁
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
c₁ : γ₁
⊢ ¬∃ a₂ b₂ c₂, a = inr a₂ ∧ b = inr b₂ ∧ inl c₁ = inr c₂ ∧ c₂ ∈ g a₂ b₂

Next tactic:
simp only [inl.injEq, exists_and_left, exists_eq_left']
theorem inl_mem_sumLift₂ {c₁ : γ₁} :
    inl c₁ ∈ sumLift₂ f g a b ↔ ∃ a₁ b₁, a = inl a₁ ∧ b = inl b₁ ∧ c₁ ∈ f a₁ b₁ := by
  rw [mem_sumLift₂, or_iff_left]
  simp only [inl.injEq, exists_and_left, exists_eq_left']
  

Proof state:
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
c₁ : γ₁
⊢ ¬∃ a₂ b₂ c₂, a = inr a₂ ∧ b = inr b₂ ∧ inl c₁ = inr c₂ ∧ c₂ ∈ g a₂ b₂

Next tactic:
rintro ⟨_, _, c₂, _, _, h, _⟩
theorem inl_mem_sumLift₂ {c₁ : γ₁} :
    inl c₁ ∈ sumLift₂ f g a b ↔ ∃ a₁ b₁, a = inl a₁ ∧ b = inl b₁ ∧ c₁ ∈ f a₁ b₁ := by
  rw [mem_sumLift₂, or_iff_left]
  simp only [inl.injEq, exists_and_left, exists_eq_left']
  rintro ⟨_, _, c₂, _, _, h, _⟩
  

Proof state:
case intro.intro.intro.intro.intro.intro
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
c₁ : γ₁
w✝¹ : α₂
w✝ : β₂
c₂ : γ₂
left✝¹ : a = inr w✝¹
left✝ : b = inr w✝
h : inl c₁ = inr c₂
right✝ : c₂ ∈ g w✝¹ w✝
⊢ False

Next tactic:
exact inl_ne_inr h
theorem inr_mem_sumLift₂ {c₂ : γ₂} :
    inr c₂ ∈ sumLift₂ f g a b ↔ ∃ a₂ b₂, a = inr a₂ ∧ b = inr b₂ ∧ c₂ ∈ g a₂ b₂ := by
  

Proof state:
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
c₂ : γ₂
⊢ inr c₂ ∈ sumLift₂ f g a b ↔ ∃ a₂ b₂, a = inr a₂ ∧ b = inr b₂ ∧ c₂ ∈ g a₂ b₂

Next tactic:
rw [mem_sumLift₂, or_iff_right]
theorem inr_mem_sumLift₂ {c₂ : γ₂} :
    inr c₂ ∈ sumLift₂ f g a b ↔ ∃ a₂ b₂, a = inr a₂ ∧ b = inr b₂ ∧ c₂ ∈ g a₂ b₂ := by
  rw [mem_sumLift₂, or_iff_right]
  

Proof state:
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
c₂ : γ₂
⊢ (∃ a₂ b₂ c₂_1, a = inr a₂ ∧ b = inr b₂ ∧ inr c₂ = inr c₂_1 ∧ c₂_1 ∈ g a₂ b₂) ↔
    ∃ a₂ b₂, a = inr a₂ ∧ b = inr b₂ ∧ c₂ ∈ g a₂ b₂
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
c₂ : γ₂
⊢ ¬∃ a₁ b₁ c₁, a = inl a₁ ∧ b = inl b₁ ∧ inr c₂ = inl c₁ ∧ c₁ ∈ f a₁ b₁

Next tactic:
simp only [inr.injEq, exists_and_left, exists_eq_left']
theorem inr_mem_sumLift₂ {c₂ : γ₂} :
    inr c₂ ∈ sumLift₂ f g a b ↔ ∃ a₂ b₂, a = inr a₂ ∧ b = inr b₂ ∧ c₂ ∈ g a₂ b₂ := by
  rw [mem_sumLift₂, or_iff_right]
  simp only [inr.injEq, exists_and_left, exists_eq_left']
  

Proof state:
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
c₂ : γ₂
⊢ ¬∃ a₁ b₁ c₁, a = inl a₁ ∧ b = inl b₁ ∧ inr c₂ = inl c₁ ∧ c₁ ∈ f a₁ b₁

Next tactic:
rintro ⟨_, _, c₂, _, _, h, _⟩
theorem inr_mem_sumLift₂ {c₂ : γ₂} :
    inr c₂ ∈ sumLift₂ f g a b ↔ ∃ a₂ b₂, a = inr a₂ ∧ b = inr b₂ ∧ c₂ ∈ g a₂ b₂ := by
  rw [mem_sumLift₂, or_iff_right]
  simp only [inr.injEq, exists_and_left, exists_eq_left']
  rintro ⟨_, _, c₂, _, _, h, _⟩
  

Proof state:
case intro.intro.intro.intro.intro.intro
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
c₂✝ : γ₂
w✝¹ : α₁
w✝ : β₁
c₂ : γ₁
left✝¹ : a = inl w✝¹
left✝ : b = inl w✝
h : inr c₂✝ = inl c₂
right✝ : c₂ ∈ f w✝¹ w✝
⊢ False

Next tactic:
exact inr_ne_inl h
theorem sumLift₂_eq_empty :
    sumLift₂ f g a b = ∅ ↔
      (∀ a₁ b₁, a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
        ∀ a₂ b₂, a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅ := by
  

Proof state:
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
⊢ sumLift₂ f g a b = ∅ ↔
    (∀ (a₁ : α₁) (b₁ : β₁), a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
      ∀ (a₂ : α₂) (b₂ : β₂), a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅

Next tactic:
refine' ⟨fun h ↦ _, fun h ↦ _⟩
theorem sumLift₂_eq_empty :
    sumLift₂ f g a b = ∅ ↔
      (∀ a₁ b₁, a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
        ∀ a₂ b₂, a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅ := by
  refine' ⟨fun h ↦ _, fun h ↦ _⟩
  · 

Proof state:
case refine'_1
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
h : sumLift₂ f g a b = ∅
⊢ (∀ (a₁ : α₁) (b₁ : β₁), a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
    ∀ (a₂ : α₂) (b₂ : β₂), a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅

Next tactic:
constructor
theorem sumLift₂_eq_empty :
    sumLift₂ f g a b = ∅ ↔
      (∀ a₁ b₁, a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
        ∀ a₂ b₂, a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅ := by
  refine' ⟨fun h ↦ _, fun h ↦ _⟩
  · constructor <;>
    · 

Proof state:
case refine'_1.left
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
h : sumLift₂ f g a b = ∅
⊢ ∀ (a₁ : α₁) (b₁ : β₁), a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅

Next tactic:
rintro a b rfl rfl
theorem sumLift₂_eq_empty :
    sumLift₂ f g a b = ∅ ↔
      (∀ a₁ b₁, a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
        ∀ a₂ b₂, a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅ := by
  refine' ⟨fun h ↦ _, fun h ↦ _⟩
  · constructor <;>
    · rintro a b rfl rfl
      

Proof state:
case refine'_1.left
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
c : γ₁ ⊕ γ₂
a : α₁
b : β₁
h : sumLift₂ f g (inl a) (inl b) = ∅
⊢ f a b = ∅

Next tactic:
exact map_eq_empty.1 h
theorem sumLift₂_eq_empty :
    sumLift₂ f g a b = ∅ ↔
      (∀ a₁ b₁, a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
        ∀ a₂ b₂, a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅ := by
  refine' ⟨fun h ↦ _, fun h ↦ _⟩
  · constructor <;>
    · 

Proof state:
case refine'_1.right
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
h : sumLift₂ f g a b = ∅
⊢ ∀ (a₂ : α₂) (b₂ : β₂), a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅

Next tactic:
rintro a b rfl rfl
theorem sumLift₂_eq_empty :
    sumLift₂ f g a b = ∅ ↔
      (∀ a₁ b₁, a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
        ∀ a₂ b₂, a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅ := by
  refine' ⟨fun h ↦ _, fun h ↦ _⟩
  · constructor <;>
    · rintro a b rfl rfl
      

Proof state:
case refine'_1.right
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
c : γ₁ ⊕ γ₂
a : α₂
b : β₂
h : sumLift₂ f g (inr a) (inr b) = ∅
⊢ g a b = ∅

Next tactic:
exact map_eq_empty.1 h
theorem sumLift₂_eq_empty :
    sumLift₂ f g a b = ∅ ↔
      (∀ a₁ b₁, a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
        ∀ a₂ b₂, a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅ := by
  refine' ⟨fun h ↦ _, fun h ↦ _⟩
  · constructor <;>
    · rintro a b rfl rfl
      exact map_eq_empty.1 h
  

Proof state:
case refine'_2
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
h :
  (∀ (a₁ : α₁) (b₁ : β₁), a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
    ∀ (a₂ : α₂) (b₂ : β₂), a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅
⊢ sumLift₂ f g a b = ∅

Next tactic:
cases a
theorem sumLift₂_eq_empty :
    sumLift₂ f g a b = ∅ ↔
      (∀ a₁ b₁, a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
        ∀ a₂ b₂, a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅ := by
  refine' ⟨fun h ↦ _, fun h ↦ _⟩
  · constructor <;>
    · rintro a b rfl rfl
      exact map_eq_empty.1 h
  cases a <;> 

Proof state:
case refine'_2.inl
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
val✝ : α₁
h :
  (∀ (a₁ : α₁) (b₁ : β₁), inl val✝ = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
    ∀ (a₂ : α₂) (b₂ : β₂), inl val✝ = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅
⊢ sumLift₂ f g (inl val✝) b = ∅

Next tactic:
cases b
theorem sumLift₂_eq_empty :
    sumLift₂ f g a b = ∅ ↔
      (∀ a₁ b₁, a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
        ∀ a₂ b₂, a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅ := by
  refine' ⟨fun h ↦ _, fun h ↦ _⟩
  · constructor <;>
    · rintro a b rfl rfl
      exact map_eq_empty.1 h
  cases a <;> 

Proof state:
case refine'_2.inr
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
val✝ : α₂
h :
  (∀ (a₁ : α₁) (b₁ : β₁), inr val✝ = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
    ∀ (a₂ : α₂) (b₂ : β₂), inr val✝ = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅
⊢ sumLift₂ f g (inr val✝) b = ∅

Next tactic:
cases b
theorem sumLift₂_eq_empty :
    sumLift₂ f g a b = ∅ ↔
      (∀ a₁ b₁, a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
        ∀ a₂ b₂, a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅ := by
  refine' ⟨fun h ↦ _, fun h ↦ _⟩
  · constructor <;>
    · rintro a b rfl rfl
      exact map_eq_empty.1 h
  cases a <;> cases b
  · 

Proof state:
case refine'_2.inl.inl
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
c : γ₁ ⊕ γ₂
val✝¹ : α₁
val✝ : β₁
h :
  (∀ (a₁ : α₁) (b₁ : β₁), inl val✝¹ = inl a₁ → inl val✝ = inl b₁ → f a₁ b₁ = ∅) ∧
    ∀ (a₂ : α₂) (b₂ : β₂), inl val✝¹ = inr a₂ → inl val✝ = inr b₂ → g a₂ b₂ = ∅
⊢ sumLift₂ f g (inl val✝¹) (inl val✝) = ∅

Next tactic:
exact map_eq_empty.2 (h.1 _ _ rfl rfl)
theorem sumLift₂_eq_empty :
    sumLift₂ f g a b = ∅ ↔
      (∀ a₁ b₁, a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
        ∀ a₂ b₂, a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅ := by
  refine' ⟨fun h ↦ _, fun h ↦ _⟩
  · constructor <;>
    · rintro a b rfl rfl
      exact map_eq_empty.1 h
  cases a <;> cases b
  · exact map_eq_empty.2 (h.1 _ _ rfl rfl)
  · 

Proof state:
case refine'_2.inl.inr
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
c : γ₁ ⊕ γ₂
val✝¹ : α₁
val✝ : β₂
h :
  (∀ (a₁ : α₁) (b₁ : β₁), inl val✝¹ = inl a₁ → inr val✝ = inl b₁ → f a₁ b₁ = ∅) ∧
    ∀ (a₂ : α₂) (b₂ : β₂), inl val✝¹ = inr a₂ → inr val✝ = inr b₂ → g a₂ b₂ = ∅
⊢ sumLift₂ f g (inl val✝¹) (inr val✝) = ∅

Next tactic:
rfl
theorem sumLift₂_eq_empty :
    sumLift₂ f g a b = ∅ ↔
      (∀ a₁ b₁, a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
        ∀ a₂ b₂, a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅ := by
  refine' ⟨fun h ↦ _, fun h ↦ _⟩
  · constructor <;>
    · rintro a b rfl rfl
      exact map_eq_empty.1 h
  cases a <;> cases b
  · exact map_eq_empty.2 (h.1 _ _ rfl rfl)
  · rfl
  · 

Proof state:
case refine'_2.inr.inl
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
c : γ₁ ⊕ γ₂
val✝¹ : α₂
val✝ : β₁
h :
  (∀ (a₁ : α₁) (b₁ : β₁), inr val✝¹ = inl a₁ → inl val✝ = inl b₁ → f a₁ b₁ = ∅) ∧
    ∀ (a₂ : α₂) (b₂ : β₂), inr val✝¹ = inr a₂ → inl val✝ = inr b₂ → g a₂ b₂ = ∅
⊢ sumLift₂ f g (inr val✝¹) (inl val✝) = ∅

Next tactic:
rfl
theorem sumLift₂_eq_empty :
    sumLift₂ f g a b = ∅ ↔
      (∀ a₁ b₁, a = inl a₁ → b = inl b₁ → f a₁ b₁ = ∅) ∧
        ∀ a₂ b₂, a = inr a₂ → b = inr b₂ → g a₂ b₂ = ∅ := by
  refine' ⟨fun h ↦ _, fun h ↦ _⟩
  · constructor <;>
    · rintro a b rfl rfl
      exact map_eq_empty.1 h
  cases a <;> cases b
  · exact map_eq_empty.2 (h.1 _ _ rfl rfl)
  · rfl
  · rfl
  · 

Proof state:
case refine'_2.inr.inr
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
c : γ₁ ⊕ γ₂
val✝¹ : α₂
val✝ : β₂
h :
  (∀ (a₁ : α₁) (b₁ : β₁), inr val✝¹ = inl a₁ → inr val✝ = inl b₁ → f a₁ b₁ = ∅) ∧
    ∀ (a₂ : α₂) (b₂ : β₂), inr val✝¹ = inr a₂ → inr val✝ = inr b₂ → g a₂ b₂ = ∅
⊢ sumLift₂ f g (inr val✝¹) (inr val✝) = ∅

Next tactic:
exact map_eq_empty.2 (h.2 _ _ rfl rfl)
theorem sumLift₂_nonempty :
    (sumLift₂ f g a b).Nonempty ↔
      (∃ a₁ b₁, a = inl a₁ ∧ b = inl b₁ ∧ (f a₁ b₁).Nonempty) ∨
        ∃ a₂ b₂, a = inr a₂ ∧ b = inr b₂ ∧ (g a₂ b₂).Nonempty := by
  

Proof state:
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f f₁ g₁ : α₁ → β₁ → Finset γ₁
g f₂ g₂ : α₂ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
⊢ Finset.Nonempty (sumLift₂ f g a b) ↔
    (∃ a₁ b₁, a = inl a₁ ∧ b = inl b₁ ∧ Finset.Nonempty (f a₁ b₁)) ∨
      ∃ a₂ b₂, a = inr a₂ ∧ b = inr b₂ ∧ Finset.Nonempty (g a₂ b₂)

Next tactic:
simp only [nonempty_iff_ne_empty, Ne, sumLift₂_eq_empty, not_and_or, not_forall, not_imp]
lemma mem_sumLexLift :
    c ∈ sumLexLift f₁ f₂ g₁ g₂ a b ↔
      (∃ a₁ b₁ c₁, a = inl a₁ ∧ b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f₁ a₁ b₁) ∨
        (∃ a₁ b₂ c₁, a = inl a₁ ∧ b = inr b₂ ∧ c = inl c₁ ∧ c₁ ∈ g₁ a₁ b₂) ∨
          (∃ a₁ b₂ c₂, a = inl a₁ ∧ b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g₂ a₁ b₂) ∨
            ∃ a₂ b₂ c₂, a = inr a₂ ∧ b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ f₂ a₂ b₂ := by
  

Proof state:
α₁ : Type u_1
α₂ : Type u_2
β₁ : Type u_3
β₂ : Type u_4
γ₁ : Type u_5
γ₂ : Type u_6
f₁ f₁' : α₁ → β₁ → Finset γ₁
f₂ f₂' : α₂ → β₂ → Finset γ₂
g₁ g₁' : α₁ → β₂ → Finset γ₁
g₂ g₂' : α₁ → β₂ → Finset γ₂
a : α₁ ⊕ α₂
b : β₁ ⊕ β₂
c : γ₁ ⊕ γ₂
⊢ c ∈ sumLexLift f₁ f₂ g₁ g₂ a b ↔
    (∃ a₁ b₁ c₁, a = inl a₁ ∧ b = inl b₁ ∧ c = inl c₁ ∧ c₁ ∈ f₁ a₁ b₁) ∨
      (∃ a₁ b₂ c₁, a = inl a₁ ∧ b = inr b₂ ∧ c = inl c₁ ∧ c₁ ∈ g₁ a₁ b₂) ∨
        (∃ a₁ b₂ c₂, a = inl a₁ ∧ b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ g₂ a₁ b₂) ∨
          ∃ a₂ b₂ c₂, a = inr a₂ ∧ b = inr b₂ ∧ c = inr c₂ ∧ c₂ ∈ f₂ a₂ b₂

Next tactic:
constructor