Module: Mathlib.CategoryTheory.Triangulated.TStructure.AbelianSubcategory

Goal state before:
pp: case refine_2
C : Type u_1
A : Type u_2
inst✝¹¹ : Category.{v_1, u_1} C
inst✝¹⁰ : HasZeroObject C
inst✝⁹ : Preadditive C
inst✝⁸ : HasShift C ℤ
inst✝⁷ : ∀ (n : ℤ), (shiftFunctor C n).Additive
inst✝⁶ : Pretriangulated C
inst✝⁵ : Category.{v_2, u_2} A
ι : A ⥤ C
hι : ∀ ⦃X Y : A⦄ ⦃n : ℤ⦄ (f : ι.obj X ⟶ (shiftFunctor C n).obj (ι.obj Y)), n < 0 → f = 0
inst✝⁴ : Preadditive A
inst✝³ : ι.Full
inst✝² : ι.Faithful
inst✝¹ : HasFiniteProducts A
inst✝ : ι.Additive
X₁ X₂ X₃ : A
f₁ : X₁ ⟶ X₂
f₂ : X₂ ⟶ X₃
f₃ : ι.obj X₃ ⟶ (shiftFunctor C 1).obj (ι.obj X₁)
hT : Triangle.mk (ι.map f₁) (ι.map f₂) f₃ ∈ distinguishedTriangles
⊢ IsZero (contractibleTriangle (ι.obj X₃)).invRotate.obj₁

pp: case refine_3
C : Type u_1
A : Type u_2
inst✝¹¹ : Category.{v_1, u_1} C
inst✝¹⁰ : HasZeroObject C
inst✝⁹ : Preadditive C
inst✝⁸ : HasShift C ℤ
inst✝⁷ : ∀ (n : ℤ), (shiftFunctor C n).Additive
inst✝⁶ : Pretriangulated C
inst✝⁵ : Category.{v_2, u_2} A
ι : A ⥤ C
hι : ∀ ⦃X Y : A⦄ ⦃n : ℤ⦄ (f : ι.obj X ⟶ (shiftFunctor C n).obj (ι.obj Y)), n < 0 → f = 0
inst✝⁴ : Preadditive A
inst✝³ : ι.Full
inst✝² : ι.Faithful
inst✝¹ : HasFiniteProducts A
inst✝ : ι.Additive
X₁ X₂ X₃ : A
f₁ : X₁ ⟶ X₂
f₂ : X₂ ⟶ X₃
f₃ : ι.obj X₃ ⟶ (shiftFunctor C 1).obj (ι.obj X₁)
hT : Triangle.mk (ι.map f₁) (ι.map f₂) f₃ ∈ distinguishedTriangles
⊢ (Triangle.mk 0 (𝟙 (ι.obj X₃)) 0).mor₁ ≫ (Iso.refl (Triangle.mk 0 (𝟙 (ι.obj X₃)) 0).obj₂).hom =
    (⋯.iso ?refine_2).hom ≫ (contractibleTriangle (ι.obj X₃)).invRotate.mor₁

pp: case refine_4
C : Type u_1
A : Type u_2
inst✝¹¹ : Category.{v_1, u_1} C
inst✝¹⁰ : HasZeroObject C
inst✝⁹ : Preadditive C
inst✝⁸ : HasShift C ℤ
inst✝⁷ : ∀ (n : ℤ), (shiftFunctor C n).Additive
inst✝⁶ : Pretriangulated C
inst✝⁵ : Category.{v_2, u_2} A
ι : A ⥤ C
hι : ∀ ⦃X Y : A⦄ ⦃n : ℤ⦄ (f : ι.obj X ⟶ (shiftFunctor C n).obj (ι.obj Y)), n < 0 → f = 0
inst✝⁴ : Preadditive A
inst✝³ : ι.Full
inst✝² : ι.Faithful
inst✝¹ : HasFiniteProducts A
inst✝ : ι.Additive
X₁ X₂ X₃ : A
f₁ : X₁ ⟶ X₂
f₂ : X₂ ⟶ X₃
f₃ : ι.obj X₃ ⟶ (shiftFunctor C 1).obj (ι.obj X₁)
hT : Triangle.mk (ι.map f₁) (ι.map f₂) f₃ ∈ distinguishedTriangles
⊢ (Triangle.mk 0 (𝟙 (ι.obj X₃)) 0).mor₂ ≫ (Iso.refl (Triangle.mk 0 (𝟙 (ι.obj X₃)) 0).obj₃).hom =
    (Iso.refl (Triangle.mk 0 (𝟙 (ι.obj X₃)) 0).obj₂).hom ≫ (contractibleTriangle (ι.obj X₃)).invRotate.mor₂

pp: case refine_5
C : Type u_1
A : Type u_2
inst✝¹¹ : Category.{v_1, u_1} C
inst✝¹⁰ : HasZeroObject C
inst✝⁹ : Preadditive C
inst✝⁸ : HasShift C ℤ
inst✝⁷ : ∀ (n : ℤ), (shiftFunctor C n).Additive
inst✝⁶ : Pretriangulated C
inst✝⁵ : Category.{v_2, u_2} A
ι : A ⥤ C
hι : ∀ ⦃X Y : A⦄ ⦃n : ℤ⦄ (f : ι.obj X ⟶ (shiftFunctor C n).obj (ι.obj Y)), n < 0 → f = 0
inst✝⁴ : Preadditive A
inst✝³ : ι.Full
inst✝² : ι.Faithful
inst✝¹ : HasFiniteProducts A
inst✝ : ι.Additive
X₁ X₂ X₃ : A
f₁ : X₁ ⟶ X₂
f₂ : X₂ ⟶ X₃
f₃ : ι.obj X₃ ⟶ (shiftFunctor C 1).obj (ι.obj X₁)
hT : Triangle.mk (ι.map f₁) (ι.map f₂) f₃ ∈ distinguishedTriangles
⊢ (Triangle.mk 0 (𝟙 (ι.obj X₃)) 0).mor₃ ≫ (shiftFunctor C 1).map (⋯.iso ?refine_2).hom =
    (Iso.refl (Triangle.mk 0 (𝟙 (ι.obj X₃)) 0).obj₃).hom ≫ (contractibleTriangle (ι.obj X₃)).invRotate.mor₃

Tactic:
· dsimp
      rw [IsZero.iff_id_eq_zero, ← Functor.map_id, id_zero, Functor.map_zero]

Goal state after:
case refine_3
C : Type u_1
A : Type u_2
inst✝¹¹ : Category.{v_1, u_1} C
inst✝¹⁰ : HasZeroObject C
inst✝⁹ : Preadditive C
inst✝⁸ : HasShift C ℤ
inst✝⁷ : ∀ (n : ℤ), (shiftFunctor C n).Additive
inst✝⁶ : Pretriangulated C
inst✝⁵ : Category.{v_2, u_2} A
ι : A ⥤ C
hι : ∀ ⦃X Y : A⦄ ⦃n : ℤ⦄ (f : ι.obj X ⟶ (shiftFunctor C n).obj (ι.obj Y)), n < 0 → f = 0
inst✝⁴ : Preadditive A
inst✝³ : ι.Full
inst✝² : ι.Faithful
inst✝¹ : HasFiniteProducts A
inst✝ : ι.Additive
X₁ X₂ X₃ : A
f₁ : X₁ ⟶ X₂
f₂ : X₂ ⟶ X₃
f₃ : ι.obj X₃ ⟶ (shiftFunctor C 1).obj (ι.obj X₁)
hT : Triangle.mk (ι.map f₁) (ι.map f₂) f₃ ∈ distinguishedTriangles
⊢ (Triangle.mk 0 (𝟙 (ι.obj X₃)) 0).mor₁ ≫ (Iso.refl (Triangle.mk 0 (𝟙 (ι.obj X₃)) 0).obj₂).hom =
    (⋯.iso ⋯).hom ≫ (contractibleTriangle (ι.obj X₃)).invRotate.mor₁

case refine_4
C : Type u_1
A : Type u_2
inst✝¹¹ : Category.{v_1, u_1} C
inst✝¹⁰ : HasZeroObject C
inst✝⁹ : Preadditive C
inst✝⁸ : HasShift C ℤ
inst✝⁷ : ∀ (n : ℤ), (shiftFunctor C n).Additive
inst✝⁶ : Pretriangulated C
inst✝⁵ : Category.{v_2, u_2} A
ι : A ⥤ C
hι : ∀ ⦃X Y : A⦄ ⦃n : ℤ⦄ (f : ι.obj X ⟶ (shiftFunctor C n).obj (ι.obj Y)), n < 0 → f = 0
inst✝⁴ : Preadditive A
inst✝³ : ι.Full
inst✝² : ι.Faithful
inst✝¹ : HasFiniteProducts A
inst✝ : ι.Additive
X₁ X₂ X₃ : A
f₁ : X₁ ⟶ X₂
f₂ : X₂ ⟶ X₃
f₃ : ι.obj X₃ ⟶ (shiftFunctor C 1).obj (ι.obj X₁)
hT : Triangle.mk (ι.map f₁) (ι.map f₂) f₃ ∈ distinguishedTriangles
⊢ (Triangle.mk 0 (𝟙 (ι.obj X₃)) 0).mor₂ ≫ (Iso.refl (Triangle.mk 0 (𝟙 (ι.obj X₃)) 0).obj₃).hom =
    (Iso.refl (Triangle.mk 0 (𝟙 (ι.obj X₃)) 0).obj₂).hom ≫ (contractibleTriangle (ι.obj X₃)).invRotate.mor₂

case refine_5
C : Type u_1
A : Type u_2
inst✝¹¹ : Category.{v_1, u_1} C
inst✝¹⁰ : HasZeroObject C
inst✝⁹ : Preadditive C
inst✝⁸ : HasShift C ℤ
inst✝⁷ : ∀ (n : ℤ), (shiftFunctor C n).Additive
inst✝⁶ : Pretriangulated C
inst✝⁵ : Category.{v_2, u_2} A
ι : A ⥤ C
hι : ∀ ⦃X Y : A⦄ ⦃n : ℤ⦄ (f : ι.obj X ⟶ (shiftFunctor C n).obj (ι.obj Y)), n < 0 → f = 0
inst✝⁴ : Preadditive A
inst✝³ : ι.Full
inst✝² : ι.Faithful
inst✝¹ : HasFiniteProducts A
inst✝ : ι.Additive
X₁ X₂ X₃ : A
f₁ : X₁ ⟶ X₂
f₂ : X₂ ⟶ X₃
f₃ : ι.obj X₃ ⟶ (shiftFunctor C 1).obj (ι.obj X₁)
hT : Triangle.mk (ι.map f₁) (ι.map f₂) f₃ ∈ distinguishedTriangles
⊢ (Triangle.mk 0 (𝟙 (ι.obj X₃)) 0).mor₃ ≫ (shiftFunctor C 1).map (⋯.iso ⋯).hom =
    (Iso.refl (Triangle.mk 0 (𝟙 (ι.obj X₃)) 0).obj₃).hom ≫ (contractibleTriangle (ι.obj X₃)).invRotate.mor₃