Theorem: CategoryTheory.Pretriangulated.exists_iso_of_arrow_iso
File: Mathlib/CategoryTheory/Triangulated/Pretriangulated.lean

Proof steps:
state_before: C : Type u
inst✝⁴ : Category.{v, u} C
inst✝³ : HasZeroObject C
inst✝² : HasShift C ℤ
inst✝¹ : Preadditive C
inst✝ : ∀ (n : ℤ), (shiftFunctor C n).Additive
hC : Pretriangulated C
T₁ T₂ : Triangle C
hT₁ : T₁ ∈ distinguishedTriangles
hT₂ : T₂ ∈ distinguishedTriangles
e : Arrow.mk T₁.mor₁ ≅ Arrow.mk T₂.mor₁
⊢ ∃ e', e'.hom.hom₁ = e.hom.left ∧ e'.hom.hom₂ = e.hom.right
state_after: C : Type u
inst✝⁴ : Category.{v, u} C
inst✝³ : HasZeroObject C
inst✝² : HasShift C ℤ
inst✝¹ : Preadditive C
inst✝ : ∀ (n : ℤ), (shiftFunctor C n).Additive
hC : Pretriangulated C
T₁ T₂ : Triangle C
hT₁ : T₁ ∈ distinguishedTriangles
hT₂ : T₂ ∈ distinguishedTriangles
e : Arrow.mk T₁.mor₁ ≅ Arrow.mk T₂.mor₁
φ : T₁ ⟶ T₂ := completeDistinguishedTriangleMorphism T₁ T₂ hT₁ hT₂ e.hom.left e.hom.right ⋯
⊢ ∃ e', e'.hom.hom₁ = e.hom.left ∧ e'.hom.hom₂ = e.hom.right
tactic: let φ := completeDistinguishedTriangleMorphism T₁ T₂ hT₁ hT₂ e.hom.left e.hom.right e.hom.w.symm
state_before: C : Type u
inst✝⁴ : Category.{v, u} C
inst✝³ : HasZeroObject C
inst✝² : HasShift C ℤ
inst✝¹ : Preadditive C
inst✝ : ∀ (n : ℤ), (shiftFunctor C n).Additive
hC : Pretriangulated C
T₁ T₂ : Triangle C
hT₁ : T₁ ∈ distinguishedTriangles
hT₂ : T₂ ∈ distinguishedTriangles
e : Arrow.mk T₁.mor₁ ≅ Arrow.mk T₂.mor₁
φ : T₁ ⟶ T₂ := completeDistinguishedTriangleMorphism T₁ T₂ hT₁ hT₂ e.hom.left e.hom.right ⋯
⊢ ∃ e', e'.hom.hom₁ = e.hom.left ∧ e'.hom.hom₂ = e.hom.right
state_after: C : Type u
inst✝⁴ : Category.{v, u} C
inst✝³ : HasZeroObject C
inst✝² : HasShift C ℤ
inst✝¹ : Preadditive C
inst✝ : ∀ (n : ℤ), (shiftFunctor C n).Additive
hC : Pretriangulated C
T₁ T₂ : Triangle C
hT₁ : T₁ ∈ distinguishedTriangles
hT₂ : T₂ ∈ distinguishedTriangles
e : Arrow.mk T₁.mor₁ ≅ Arrow.mk T₂.mor₁
φ : T₁ ⟶ T₂ := completeDistinguishedTriangleMorphism T₁ T₂ hT₁ hT₂ e.hom.left e.hom.right ⋯
this : IsIso φ.hom₁
⊢ ∃ e', e'.hom.hom₁ = e.hom.left ∧ e'.hom.hom₂ = e.hom.right
tactic: have : IsIso φ.hom₁ := by dsimp [φ]; infer_instance
state_before: C : Type u
inst✝⁴ : Category.{v, u} C
inst✝³ : HasZeroObject C
inst✝² : HasShift C ℤ
inst✝¹ : Preadditive C
inst✝ : ∀ (n : ℤ), (shiftFunctor C n).Additive
hC : Pretriangulated C
T₁ T₂ : Triangle C
hT₁ : T₁ ∈ distinguishedTriangles
hT₂ : T₂ ∈ distinguishedTriangles
e : Arrow.mk T₁.mor₁ ≅ Arrow.mk T₂.mor₁
φ : T₁ ⟶ T₂ := completeDistinguishedTriangleMorphism T₁ T₂ hT₁ hT₂ e.hom.left e.hom.right ⋯
this : IsIso φ.hom₁
⊢ ∃ e', e'.hom.hom₁ = e.hom.left ∧ e'.hom.hom₂ = e.hom.right
state_after: C : Type u
inst✝⁴ : Category.{v, u} C
inst✝³ : HasZeroObject C
inst✝² : HasShift C ℤ
inst✝¹ : Preadditive C
inst✝ : ∀ (n : ℤ), (shiftFunctor C n).Additive
hC : Pretriangulated C
T₁ T₂ : Triangle C
hT₁ : T₁ ∈ distinguishedTriangles
hT₂ : T₂ ∈ distinguishedTriangles
e : Arrow.mk T₁.mor₁ ≅ Arrow.mk T₂.mor₁
φ : T₁ ⟶ T₂ := completeDistinguishedTriangleMorphism T₁ T₂ hT₁ hT₂ e.hom.left e.hom.right ⋯
this✝ : IsIso φ.hom₁
this : IsIso φ.hom₂
⊢ ∃ e', e'.hom.hom₁ = e.hom.left ∧ e'.hom.hom₂ = e.hom.right
tactic: have : IsIso φ.hom₂ := by dsimp [φ]; infer_instance
state_before: C : Type u
inst✝⁴ : Category.{v, u} C
inst✝³ : HasZeroObject C
inst✝² : HasShift C ℤ
inst✝¹ : Preadditive C
inst✝ : ∀ (n : ℤ), (shiftFunctor C n).Additive
hC : Pretriangulated C
T₁ T₂ : Triangle C
hT₁ : T₁ ∈ distinguishedTriangles
hT₂ : T₂ ∈ distinguishedTriangles
e : Arrow.mk T₁.mor₁ ≅ Arrow.mk T₂.mor₁
φ : T₁ ⟶ T₂ := completeDistinguishedTriangleMorphism T₁ T₂ hT₁ hT₂ e.hom.left e.hom.right ⋯
this✝ : IsIso φ.hom₁
this : IsIso φ.hom₂
⊢ ∃ e', e'.hom.hom₁ = e.hom.left ∧ e'.hom.hom₂ = e.hom.right
state_after: C : Type u
inst✝⁴ : Category.{v, u} C
inst✝³ : HasZeroObject C
inst✝² : HasShift C ℤ
inst✝¹ : Preadditive C
inst✝ : ∀ (n : ℤ), (shiftFunctor C n).Additive
hC : Pretriangulated C
T₁ T₂ : Triangle C
hT₁ : T₁ ∈ distinguishedTriangles
hT₂ : T₂ ∈ distinguishedTriangles
e : Arrow.mk T₁.mor₁ ≅ Arrow.mk T₂.mor₁
φ : T₁ ⟶ T₂ := completeDistinguishedTriangleMorphism T₁ T₂ hT₁ hT₂ e.hom.left e.hom.right ⋯
this✝¹ : IsIso φ.hom₁
this✝ : IsIso φ.hom₂
this : IsIso φ.hom₃
⊢ ∃ e', e'.hom.hom₁ = e.hom.left ∧ e'.hom.hom₂ = e.hom.right
tactic: have : IsIso φ.hom₃ := isIso₃_of_isIso₁₂ φ hT₁ hT₂ inferInstance inferInstance
state_before: C : Type u
inst✝⁴ : Category.{v, u} C
inst✝³ : HasZeroObject C
inst✝² : HasShift C ℤ
inst✝¹ : Preadditive C
inst✝ : ∀ (n : ℤ), (shiftFunctor C n).Additive
hC : Pretriangulated C
T₁ T₂ : Triangle C
hT₁ : T₁ ∈ distinguishedTriangles
hT₂ : T₂ ∈ distinguishedTriangles
e : Arrow.mk T₁.mor₁ ≅ Arrow.mk T₂.mor₁
φ : T₁ ⟶ T₂ := completeDistinguishedTriangleMorphism T₁ T₂ hT₁ hT₂ e.hom.left e.hom.right ⋯
this✝¹ : IsIso φ.hom₁
this✝ : IsIso φ.hom₂
this : IsIso φ.hom₃
⊢ ∃ e', e'.hom.hom₁ = e.hom.left ∧ e'.hom.hom₂ = e.hom.right
state_after: C : Type u
inst✝⁴ : Category.{v, u} C
inst✝³ : HasZeroObject C
inst✝² : HasShift C ℤ
inst✝¹ : Preadditive C
inst✝ : ∀ (n : ℤ), (shiftFunctor C n).Additive
hC : Pretriangulated C
T₁ T₂ : Triangle C
hT₁ : T₁ ∈ distinguishedTriangles
hT₂ : T₂ ∈ distinguishedTriangles
e : Arrow.mk T₁.mor₁ ≅ Arrow.mk T₂.mor₁
φ : T₁ ⟶ T₂ := completeDistinguishedTriangleMorphism T₁ T₂ hT₁ hT₂ e.hom.left e.hom.right ⋯
this✝² : IsIso φ.hom₁
this✝¹ : IsIso φ.hom₂
this✝ : IsIso φ.hom₃
this : IsIso φ
⊢ ∃ e', e'.hom.hom₁ = e.hom.left ∧ e'.hom.hom₂ = e.hom.right
tactic: have : IsIso φ := by
    apply Triangle.isIso_of_isIsos
    all_goals infer_instance
state_before: C : Type u
inst✝⁴ : Category.{v, u} C
inst✝³ : HasZeroObject C
inst✝² : HasShift C ℤ
inst✝¹ : Preadditive C
inst✝ : ∀ (n : ℤ), (shiftFunctor C n).Additive
hC : Pretriangulated C
T₁ T₂ : Triangle C
hT₁ : T₁ ∈ distinguishedTriangles
hT₂ : T₂ ∈ distinguishedTriangles
e : Arrow.mk T₁.mor₁ ≅ Arrow.mk T₂.mor₁
φ : T₁ ⟶ T₂ := completeDistinguishedTriangleMorphism T₁ T₂ hT₁ hT₂ e.hom.left e.hom.right ⋯
this✝² : IsIso φ.hom₁
this✝¹ : IsIso φ.hom₂
this✝ : IsIso φ.hom₃
this : IsIso φ
⊢ ∃ e', e'.hom.hom₁ = e.hom.left ∧ e'.hom.hom₂ = e.hom.right
state_after: no goals
tactic: exact ⟨asIso φ, by simp [φ], by simp [φ]⟩