Theorem: AlgebraicTopology.DoldKan.Γ₀.Obj.map_on_summand₀
File: Mathlib/AlgebraicTopology/DoldKan/FunctorGamma.lean

Proof steps:
state_before: C : Type u_1
inst✝⁴ : Category.{u_2, u_1} C
inst✝³ : Preadditive C
K K' : ChainComplex C ℕ
f : K ⟶ K'
Δ✝ Δ'✝ Δ''✝ : SimplexCategory
inst✝² : HasFiniteCoproducts C
Δ Δ' : SimplexCategoryᵒᵖ
A : Splitting.IndexSet Δ
θ : Δ ⟶ Δ'
Δ'' : SimplexCategory
e : unop Δ' ⟶ Δ''
i : Δ'' ⟶ unop A.fst
inst✝¹ : Epi e
inst✝ : Mono i
fac : e ≫ i = θ.unop ≫ A.e
⊢ Sigma.ι (summand K Δ) A ≫ map K θ = Termwise.mapMono K i ≫ Sigma.ι (summand K Δ') (Splitting.IndexSet.mk e)
state_after: C : Type u_1
inst✝⁴ : Category.{u_2, u_1} C
inst✝³ : Preadditive C
K K' : ChainComplex C ℕ
f : K ⟶ K'
Δ✝ Δ'✝ Δ''✝ : SimplexCategory
inst✝² : HasFiniteCoproducts C
Δ Δ' : SimplexCategoryᵒᵖ
A : Splitting.IndexSet Δ
θ : Δ ⟶ Δ'
Δ'' : SimplexCategory
e : unop Δ' ⟶ Δ''
i : Δ'' ⟶ unop A.fst
inst✝¹ : Epi e
inst✝ : Mono i
fac : e ≫ i = θ.unop ≫ A.e
⊢ Termwise.mapMono K (image.ι (θ.unop ≫ A.e)) ≫ Sigma.ι (summand K Δ') (A.pull θ) =
    Termwise.mapMono K i ≫ Sigma.ι (summand K Δ') (Splitting.IndexSet.mk e)
tactic: simp only [map, colimit.ι_desc, Cofan.mk_ι_app]
state_before: C : Type u_1
inst✝⁴ : Category.{u_2, u_1} C
inst✝³ : Preadditive C
K K' : ChainComplex C ℕ
f : K ⟶ K'
Δ✝ Δ'✝ Δ''✝ : SimplexCategory
inst✝² : HasFiniteCoproducts C
Δ Δ' : SimplexCategoryᵒᵖ
A : Splitting.IndexSet Δ
θ : Δ ⟶ Δ'
Δ'' : SimplexCategory
e : unop Δ' ⟶ Δ''
i : Δ'' ⟶ unop A.fst
inst✝¹ : Epi e
inst✝ : Mono i
fac : e ≫ i = θ.unop ≫ A.e
⊢ Termwise.mapMono K (image.ι (θ.unop ≫ A.e)) ≫ Sigma.ι (summand K Δ') (A.pull θ) =
    Termwise.mapMono K i ≫ Sigma.ι (summand K Δ') (Splitting.IndexSet.mk e)
state_after: C : Type u_1
inst✝⁴ : Category.{u_2, u_1} C
inst✝³ : Preadditive C
K K' : ChainComplex C ℕ
f : K ⟶ K'
Δ✝ Δ'✝ Δ''✝ : SimplexCategory
inst✝² : HasFiniteCoproducts C
Δ Δ' : SimplexCategoryᵒᵖ
A : Splitting.IndexSet Δ
θ : Δ ⟶ Δ'
Δ'' : SimplexCategory
e : unop Δ' ⟶ Δ''
i : Δ'' ⟶ unop A.fst
inst✝¹ : Epi e
inst✝ : Mono i
fac : e ≫ i = θ.unop ≫ A.e
h : image (θ.unop ≫ A.e) = Δ''
⊢ Termwise.mapMono K (image.ι (θ.unop ≫ A.e)) ≫ Sigma.ι (summand K Δ') (A.pull θ) =
    Termwise.mapMono K i ≫ Sigma.ι (summand K Δ') (Splitting.IndexSet.mk e)
tactic: have h := SimplexCategory.image_eq fac
state_before: C : Type u_1
inst✝⁴ : Category.{u_2, u_1} C
inst✝³ : Preadditive C
K K' : ChainComplex C ℕ
f : K ⟶ K'
Δ✝ Δ'✝ Δ''✝ : SimplexCategory
inst✝² : HasFiniteCoproducts C
Δ Δ' : SimplexCategoryᵒᵖ
A : Splitting.IndexSet Δ
θ : Δ ⟶ Δ'
Δ'' : SimplexCategory
e : unop Δ' ⟶ Δ''
i : Δ'' ⟶ unop A.fst
inst✝¹ : Epi e
inst✝ : Mono i
fac : e ≫ i = θ.unop ≫ A.e
h : image (θ.unop ≫ A.e) = Δ''
⊢ Termwise.mapMono K (image.ι (θ.unop ≫ A.e)) ≫ Sigma.ι (summand K Δ') (A.pull θ) =
    Termwise.mapMono K i ≫ Sigma.ι (summand K Δ') (Splitting.IndexSet.mk e)
state_after: C : Type u_1
inst✝⁴ : Category.{u_2, u_1} C
inst✝³ : Preadditive C
K K' : ChainComplex C ℕ
f : K ⟶ K'
Δ✝ Δ'✝ Δ'' : SimplexCategory
inst✝² : HasFiniteCoproducts C
Δ Δ' : SimplexCategoryᵒᵖ
A : Splitting.IndexSet Δ
θ : Δ ⟶ Δ'
e : unop Δ' ⟶ image (θ.unop ≫ A.e)
i : image (θ.unop ≫ A.e) ⟶ unop A.fst
inst✝¹ : Epi e
inst✝ : Mono i
fac : e ≫ i = θ.unop ≫ A.e
⊢ Termwise.mapMono K (image.ι (θ.unop ≫ A.e)) ≫ Sigma.ι (summand K Δ') (A.pull θ) =
    Termwise.mapMono K i ≫ Sigma.ι (summand K Δ') (Splitting.IndexSet.mk e)
tactic: subst h
state_before: C : Type u_1
inst✝⁴ : Category.{u_2, u_1} C
inst✝³ : Preadditive C
K K' : ChainComplex C ℕ
f : K ⟶ K'
Δ✝ Δ'✝ Δ'' : SimplexCategory
inst✝² : HasFiniteCoproducts C
Δ Δ' : SimplexCategoryᵒᵖ
A : Splitting.IndexSet Δ
θ : Δ ⟶ Δ'
e : unop Δ' ⟶ image (θ.unop ≫ A.e)
i : image (θ.unop ≫ A.e) ⟶ unop A.fst
inst✝¹ : Epi e
inst✝ : Mono i
fac : e ≫ i = θ.unop ≫ A.e
⊢ Termwise.mapMono K (image.ι (θ.unop ≫ A.e)) ≫ Sigma.ι (summand K Δ') (A.pull θ) =
    Termwise.mapMono K i ≫ Sigma.ι (summand K Δ') (Splitting.IndexSet.mk e)
state_after: case e_a.e_i
C : Type u_1
inst✝⁴ : Category.{u_2, u_1} C
inst✝³ : Preadditive C
K K' : ChainComplex C ℕ
f : K ⟶ K'
Δ✝ Δ'✝ Δ'' : SimplexCategory
inst✝² : HasFiniteCoproducts C
Δ Δ' : SimplexCategoryᵒᵖ
A : Splitting.IndexSet Δ
θ : Δ ⟶ Δ'
e : unop Δ' ⟶ image (θ.unop ≫ A.e)
i : image (θ.unop ≫ A.e) ⟶ unop A.fst
inst✝¹ : Epi e
inst✝ : Mono i
fac : e ≫ i = θ.unop ≫ A.e
⊢ image.ι (θ.unop ≫ A.e) = i

case e_a.h.e_6.h
C : Type u_1
inst✝⁴ : Category.{u_2, u_1} C
inst✝³ : Preadditive C
K K' : ChainComplex C ℕ
f : K ⟶ K'
Δ✝ Δ'✝ Δ'' : SimplexCategory
inst✝² : HasFiniteCoproducts C
Δ Δ' : SimplexCategoryᵒᵖ
A : Splitting.IndexSet Δ
θ : Δ ⟶ Δ'
e : unop Δ' ⟶ image (θ.unop ≫ A.e)
i : image (θ.unop ≫ A.e) ⟶ unop A.fst
inst✝¹ : Epi e
inst✝ : Mono i
fac : e ≫ i = θ.unop ≫ A.e
⊢ A.pull θ = Splitting.IndexSet.mk e
tactic: congr