Theorem: CochainComplex.mappingConeCompTriangleh_comm₁
File: Mathlib/Algebra/Homology/HomotopyCategory/Triangulated.lean

Proof steps:
state_before: C : Type u_1
inst✝³ : Category.{u_2, u_1} C
inst✝² : Preadditive C
inst✝¹ : HasZeroObject C
inst✝ : HasBinaryBiproducts C
X₁ X₂ X₃ : CochainComplex C ℤ
f : X₁ ⟶ X₂
g : X₂ ⟶ X₃
⊢ (mappingConeCompTriangleh f g).mor₂ ≫
      (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (mappingConeCompHomotopyEquiv f g).hom =
    (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (inr (mappingConeCompTriangle f g).mor₁)
state_after: C : Type u_1
inst✝³ : Category.{u_2, u_1} C
inst✝² : Preadditive C
inst✝¹ : HasZeroObject C
inst✝ : HasBinaryBiproducts C
X₁ X₂ X₃ : CochainComplex C ℤ
f : X₁ ⟶ X₂
g : X₂ ⟶ X₃
⊢ (mappingConeCompTriangleh f g).mor₂ ≫
      (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (mappingConeCompHomotopyEquiv f g).hom ≫
        (HomotopyCategory.isoOfHomotopyEquiv (mappingConeCompHomotopyEquiv f g)).inv =
    (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (inr (mappingConeCompTriangle f g).mor₁) ≫
      (HomotopyCategory.isoOfHomotopyEquiv (mappingConeCompHomotopyEquiv f g)).inv
tactic: rw [← cancel_mono (HomotopyCategory.isoOfHomotopyEquiv
      (mappingConeCompHomotopyEquiv f g)).inv, assoc]
state_before: C : Type u_1
inst✝³ : Category.{u_2, u_1} C
inst✝² : Preadditive C
inst✝¹ : HasZeroObject C
inst✝ : HasBinaryBiproducts C
X₁ X₂ X₃ : CochainComplex C ℤ
f : X₁ ⟶ X₂
g : X₂ ⟶ X₃
⊢ (mappingConeCompTriangleh f g).mor₂ ≫
      (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (mappingConeCompHomotopyEquiv f g).hom ≫
        (HomotopyCategory.isoOfHomotopyEquiv (mappingConeCompHomotopyEquiv f g)).inv =
    (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (inr (mappingConeCompTriangle f g).mor₁) ≫
      (HomotopyCategory.isoOfHomotopyEquiv (mappingConeCompHomotopyEquiv f g)).inv
state_after: C : Type u_1
inst✝³ : Category.{u_2, u_1} C
inst✝² : Preadditive C
inst✝¹ : HasZeroObject C
inst✝ : HasBinaryBiproducts C
X₁ X₂ X₃ : CochainComplex C ℤ
f : X₁ ⟶ X₂
g : X₂ ⟶ X₃
⊢ (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (map (f ≫ g) g f (𝟙 X₃) ⋯) ≫
      (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (mappingConeCompHomotopyEquiv f g).hom ≫
        (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (mappingConeCompHomotopyEquiv f g).inv =
    (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (inr (map f (f ≫ g) (𝟙 X₁) g ⋯)) ≫
      (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (mappingConeCompHomotopyEquiv f g).inv
tactic: dsimp [mappingConeCompTriangleh]
state_before: C : Type u_1
inst✝³ : Category.{u_2, u_1} C
inst✝² : Preadditive C
inst✝¹ : HasZeroObject C
inst✝ : HasBinaryBiproducts C
X₁ X₂ X₃ : CochainComplex C ℤ
f : X₁ ⟶ X₂
g : X₂ ⟶ X₃
⊢ (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (map (f ≫ g) g f (𝟙 X₃) ⋯) ≫
      (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (mappingConeCompHomotopyEquiv f g).hom ≫
        (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (mappingConeCompHomotopyEquiv f g).inv =
    (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (inr (map f (f ≫ g) (𝟙 X₁) g ⋯)) ≫
      (HomotopyCategory.quotient C (ComplexShape.up ℤ)).map (mappingConeCompHomotopyEquiv f g).inv
state_after: no goals
tactic: rw [← Functor.map_comp, ← Functor.map_comp, ← Functor.map_comp,
    mappingConeCompHomotopyEquiv_hom_inv_id, comp_id,
    mappingConeCompHomotopyEquiv_comm₁ f g,
    mappingConeCompTriangle_mor₂]