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equivalence_unit_iso : dold_kan.equivalence.unit_iso = (ε : 𝟭 (simplicial_object C) ≅ N ⋙ Γ)
compatibility.equivalence_unit_iso_eq hε
lemma
category_theory.idempotents.dold_kan.equivalence_unit_iso
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/equivalence_pseudoabelian.lean
[ "algebraic_topology.dold_kan.equivalence_additive", "algebraic_topology.dold_kan.compatibility", "category_theory.idempotents.simplicial_object" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
higher_faces_vanish {Y : C} {n : ℕ} (q : ℕ) (φ : Y ⟶ X _[n+1]) : Prop
∀ (j : fin (n+1)), (n+1 ≤ (j : ℕ) + q) → φ ≫ X.δ j.succ = 0
def
algebraic_topology.dold_kan.higher_faces_vanish
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/faces.lean
[ "algebraic_topology.dold_kan.homotopies", "tactic.ring_exp" ]
[]
A morphism `φ : Y ⟶ X _[n+1]` satisfies `higher_faces_vanish q φ` when the compositions `φ ≫ X.δ j` are `0` for `j ≥ max 1 (n+2-q)`. When `q ≤ n+1`, it basically means that the composition `φ ≫ X.δ j` are `0` for the `q` highest possible values of a nonzero `j`. Otherwise, when `q ≥ n+2`, all the compositions `φ ≫ X.δ ...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_δ_eq_zero {Y : C} {n : ℕ} {q : ℕ} {φ : Y ⟶ X _[n+1]} (v : higher_faces_vanish q φ) (j : fin (n+2)) (hj₁ : j ≠ 0) (hj₂ : n+2 ≤ (j : ℕ) + q) : φ ≫ X.δ j = 0
begin obtain ⟨i, hi⟩ := fin.eq_succ_of_ne_zero hj₁, subst hi, apply v i, rw [← @nat.add_le_add_iff_right 1, add_assoc], simpa only [fin.coe_succ, add_assoc, add_comm 1] using hj₂, end
lemma
algebraic_topology.dold_kan.higher_faces_vanish.comp_δ_eq_zero
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/faces.lean
[ "algebraic_topology.dold_kan.homotopies", "tactic.ring_exp" ]
[ "fin.coe_succ", "fin.eq_succ_of_ne_zero" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_succ {Y : C} {n q : ℕ} {φ : Y ⟶ X _[n+1]} (v : higher_faces_vanish (q+1) φ) : higher_faces_vanish q φ
λ j hj, v j (by simpa only [← add_assoc] using le_add_right hj)
lemma
algebraic_topology.dold_kan.higher_faces_vanish.of_succ
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/faces.lean
[ "algebraic_topology.dold_kan.homotopies", "tactic.ring_exp" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_comp {Y Z : C} {q n : ℕ} {φ : Y ⟶ X _[n+1]} (v : higher_faces_vanish q φ) (f : Z ⟶ Y) : higher_faces_vanish q (f ≫ φ)
λ j hj, by rw [assoc, v j hj, comp_zero]
lemma
algebraic_topology.dold_kan.higher_faces_vanish.of_comp
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/faces.lean
[ "algebraic_topology.dold_kan.homotopies", "tactic.ring_exp" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_Hσ_eq {Y : C} {n a q : ℕ} {φ : Y ⟶ X _[n+1]} (v : higher_faces_vanish q φ) (hnaq : n=a+q) : φ ≫ (Hσ q).f (n+1) = - φ ≫ X.δ ⟨a+1, nat.succ_lt_succ (nat.lt_succ_iff.mpr (nat.le.intro hnaq.symm))⟩ ≫ X.σ ⟨a, nat.lt_succ_iff.mpr (nat.le.intro hnaq.symm)⟩
begin have hnaq_shift : Π d : ℕ, n+d=(a+d)+q, { intro d, rw [add_assoc, add_comm d, ← add_assoc, hnaq], }, rw [Hσ, homotopy.null_homotopic_map'_f (c_mk (n+2) (n+1) rfl) (c_mk (n+1) n rfl), hσ'_eq hnaq (c_mk (n+1) n rfl), hσ'_eq (hnaq_shift 1) (c_mk (n+2) (n+1) rfl)], simp only [alternating_face_map_complex....
lemma
algebraic_topology.dold_kan.higher_faces_vanish.comp_Hσ_eq
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/faces.lean
[ "algebraic_topology.dold_kan.homotopies", "tactic.ring_exp" ]
[ "fin.cast_le_mk", "fin.cast_mk", "fin.cast_succ", "fin.cast_succ_mk", "fin.coe_cast", "fin.coe_cast_le", "fin.coe_cast_succ", "fin.coe_mk", "fin.coe_pred", "fin.ext_iff", "fin.last", "fin.le_iff_coe_le_coe", "fin.nat_add_mk", "fin.pred_eq_iff_eq_succ", "fin.succ_mk", "homotopy.null_hom...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_Hσ_eq_zero {Y : C} {n q : ℕ} {φ : Y ⟶ X _[n+1]} (v : higher_faces_vanish q φ) (hqn : n<q) : φ ≫ (Hσ q).f (n+1) = 0
begin simp only [Hσ, homotopy.null_homotopic_map'_f (c_mk (n+2) (n+1) rfl) (c_mk (n+1) n rfl)], rw [hσ'_eq_zero hqn (c_mk (n+1) n rfl), comp_zero, zero_add], by_cases hqn' : n+1<q, { rw [hσ'_eq_zero hqn' (c_mk (n+2) (n+1) rfl), zero_comp, comp_zero], }, { simp only [hσ'_eq (show n+1=0+q, by linarith) (c_mk (n...
lemma
algebraic_topology.dold_kan.higher_faces_vanish.comp_Hσ_eq_zero
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/faces.lean
[ "algebraic_topology.dold_kan.homotopies", "tactic.ring_exp" ]
[ "fin.cast_le_mk", "fin.cast_mk", "fin.cast_nat_add", "fin.cast_succ_mk", "fin.coe_add_nat", "fin.coe_one", "fin.coe_pred", "fin.coe_zero", "fin.ext_iff", "fin.last", "fin.lt_iff_coe_lt_coe", "fin.mk_one", "fin.mk_zero", "fin.pred_eq_iff_eq_succ", "homotopy.null_homotopic_map'_f", "neg_...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
induction {Y : C} {n q : ℕ} {φ : Y ⟶ X _[n+1]} (v : higher_faces_vanish q φ) : higher_faces_vanish (q+1) (φ ≫ (𝟙 _ + Hσ q).f (n+1))
begin intros j hj₁, dsimp, simp only [comp_add, add_comp, comp_id], -- when n < q, the result follows immediately from the assumption by_cases hqn : n<q, { rw [v.comp_Hσ_eq_zero hqn, zero_comp, add_zero, v j (by linarith)], }, -- we now assume that n≥q, and write n=a+q cases nat.le.dest (not_lt.mp hqn) ...
lemma
algebraic_topology.dold_kan.higher_faces_vanish.induction
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/faces.lean
[ "algebraic_topology.dold_kan.homotopies", "tactic.ring_exp" ]
[ "by_contradiction", "fin.coe_mk", "fin.coe_succ", "fin.eq_zero", "fin.eta", "fin.le_iff_coe_le_coe", "fin.lt_iff_coe_lt_coe", "fin.mk_one", "fin.mk_zero", "nat.succ_le_iff", "ne.le_iff_lt" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_δ₀ {Δ Δ' : simplex_category} (i : Δ' ⟶ Δ) [mono i] : Prop
(Δ.len = Δ'.len+1) ∧ (i.to_order_hom 0 ≠ 0)
def
algebraic_topology.dold_kan.is_δ₀
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "simplex_category" ]
`is_δ₀ i` is a simple condition used to check whether a monomorphism `i` in `simplex_category` identifies to the coface map `δ 0`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iff {j : ℕ} {i : fin (j+2)} : is_δ₀ (simplex_category.δ i) ↔ i = 0
begin split, { rintro ⟨h₁, h₂⟩, by_contradiction, exact h₂ (fin.succ_above_ne_zero_zero h), }, { rintro rfl, exact ⟨rfl, fin.succ_ne_zero _⟩, }, end
lemma
algebraic_topology.dold_kan.is_δ₀.iff
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "by_contradiction", "fin.succ_above_ne_zero_zero", "fin.succ_ne_zero", "simplex_category.δ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
eq_δ₀ {n : ℕ} {i : [n] ⟶ [n+1]} [mono i] (hi : is_δ₀ i) : i = simplex_category.δ 0
begin unfreezingI { obtain ⟨j, rfl⟩ := simplex_category.eq_δ_of_mono i, }, rw iff at hi, rw hi, end
lemma
algebraic_topology.dold_kan.is_δ₀.eq_δ₀
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "simplex_category.eq_δ_of_mono", "simplex_category.δ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
summand (Δ : simplex_categoryᵒᵖ) (A : splitting.index_set Δ) : C
K.X A.1.unop.len
def
algebraic_topology.dold_kan.Γ₀.obj.summand
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[]
In the definition of `(Γ₀.obj K).obj Δ` as a direct sum indexed by `A : splitting.index_set Δ`, the summand `summand K Δ A` is `K.X A.1.len`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
obj₂ (K : chain_complex C ℕ) (Δ : simplex_categoryᵒᵖ) [has_finite_coproducts C] : C
∐ (λ (A : splitting.index_set Δ), summand K Δ A)
def
algebraic_topology.dold_kan.Γ₀.obj.obj₂
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "chain_complex" ]
The functor `Γ₀` sends a chain complex `K` to the simplicial object which sends `Δ` to the direct sum of the objects `summand K Δ A` for all `A : splitting.index_set Δ`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_mono (K : chain_complex C ℕ) {Δ' Δ : simplex_category} (i : Δ' ⟶ Δ) [mono i] : K.X Δ.len ⟶ K.X Δ'.len
begin by_cases Δ = Δ', { exact eq_to_hom (by congr'), }, { by_cases is_δ₀ i, { exact K.d Δ.len Δ'.len, }, { exact 0, }, }, end
def
algebraic_topology.dold_kan.Γ₀.obj.termwise.map_mono
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "chain_complex", "simplex_category" ]
A monomorphism `i : Δ' ⟶ Δ` induces a morphism `K.X Δ.len ⟶ K.X Δ'.len` which is the identity if `Δ = Δ'`, the differential on the complex `K` if `i = δ 0`, and zero otherwise.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_mono_id : map_mono K (𝟙 Δ) = 𝟙 _
by { unfold map_mono, simp only [eq_self_iff_true, eq_to_hom_refl, dite_eq_ite, if_true], }
lemma
algebraic_topology.dold_kan.Γ₀.obj.termwise.map_mono_id
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "dite_eq_ite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_mono_δ₀' (hi : is_δ₀ i) : map_mono K i = K.d Δ.len Δ'.len
begin unfold map_mono, classical, rw [dif_neg, dif_pos hi], unfreezingI { rintro rfl, }, simpa only [self_eq_add_right, nat.one_ne_zero] using hi.1, end
lemma
algebraic_topology.dold_kan.Γ₀.obj.termwise.map_mono_δ₀'
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_mono_δ₀ {n : ℕ} : map_mono K (δ (0 : fin (n+2))) = K.d (n+1) n
map_mono_δ₀' K _ (by rw is_δ₀.iff)
lemma
algebraic_topology.dold_kan.Γ₀.obj.termwise.map_mono_δ₀
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_mono_eq_zero (h₁ : Δ ≠ Δ') (h₂ : ¬is_δ₀ i) : map_mono K i = 0
by { unfold map_mono, rw ne.def at h₁, split_ifs, refl, }
lemma
algebraic_topology.dold_kan.Γ₀.obj.termwise.map_mono_eq_zero
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_mono_naturality : map_mono K i ≫ f.f Δ'.len = f.f Δ.len ≫ map_mono K' i
begin unfold map_mono, split_ifs, { unfreezingI { subst h, }, simp only [id_comp, eq_to_hom_refl, comp_id], }, { rw homological_complex.hom.comm, }, { rw [zero_comp, comp_zero], } end
lemma
algebraic_topology.dold_kan.Γ₀.obj.termwise.map_mono_naturality
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "homological_complex.hom.comm" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_mono_comp : map_mono K i ≫ map_mono K i' = map_mono K (i' ≫ i)
begin /- case where i : Δ' ⟶ Δ is the identity -/ by_cases h₁ : Δ = Δ', { unfreezingI { subst h₁, }, simp only [simplex_category.eq_id_of_mono i, comp_id, id_comp, map_mono_id K, eq_to_hom_refl], }, /- case where i' : Δ'' ⟶ Δ' is the identity -/ by_cases h₂ : Δ' = Δ'', { unfreezingI { subst h₂, },...
lemma
algebraic_topology.dold_kan.Γ₀.obj.termwise.map_mono_comp
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "by_contradiction", "homological_complex.d_comp_d", "nat.exists_eq_add_of_lt", "simplex_category.eq_id_of_mono" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map (K : chain_complex C ℕ) {Δ' Δ : simplex_categoryᵒᵖ} (θ : Δ ⟶ Δ') : obj₂ K Δ ⟶ obj₂ K Δ'
sigma.desc (λ A, termwise.map_mono K (image.ι (θ.unop ≫ A.e)) ≫ (sigma.ι (summand K Δ') (A.pull θ)))
def
algebraic_topology.dold_kan.Γ₀.obj.map
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "chain_complex" ]
The simplicial morphism on the simplicial object `Γ₀.obj K` induced by a morphism `Δ' → Δ` in `simplex_category` is defined on each summand associated to an `A : Γ_index_set Δ` in terms of the epi-mono factorisation of `θ ≫ A.e`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_on_summand₀ {Δ Δ' : simplex_categoryᵒᵖ} (A : splitting.index_set Δ) {θ : Δ ⟶ Δ'} {Δ'' : simplex_category} {e : Δ'.unop ⟶ Δ''} {i : Δ'' ⟶ A.1.unop} [epi e] [mono i] (fac : e ≫ i = θ.unop ≫ A.e) : (sigma.ι (summand K Δ) A) ≫ map K θ = termwise.map_mono K i ≫ sigma.ι (summand K Δ') (splitting.index_set.mk e)
begin simp only [map, colimit.ι_desc, cofan.mk_ι_app], have h := simplex_category.image_eq fac, unfreezingI { subst h, }, congr, { exact simplex_category.image_ι_eq fac, }, { dsimp only [simplicial_object.splitting.index_set.pull], congr, exact simplex_category.factor_thru_image_eq fac, }, end
lemma
algebraic_topology.dold_kan.Γ₀.obj.map_on_summand₀
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "simplex_category", "simplex_category.factor_thru_image_eq", "simplex_category.image_eq", "simplex_category.image_ι_eq", "simplicial_object.splitting.index_set.pull" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_on_summand₀' {Δ Δ' : simplex_categoryᵒᵖ} (A : splitting.index_set Δ) (θ : Δ ⟶ Δ') : (sigma.ι (summand K Δ) A) ≫ map K θ = termwise.map_mono K (image.ι (θ.unop ≫ A.e)) ≫ sigma.ι (summand K _) (A.pull θ)
map_on_summand₀ K A (A.fac_pull θ)
lemma
algebraic_topology.dold_kan.Γ₀.obj.map_on_summand₀'
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
obj (K : chain_complex C ℕ) : simplicial_object C
{ obj := λ Δ, obj.obj₂ K Δ, map := λ Δ Δ' θ, obj.map K θ, map_id' := λ Δ, begin ext A, cases A, have fac : A.e ≫ 𝟙 A.1.unop = (𝟙 Δ).unop ≫ A.e := by rw [unop_id, comp_id, id_comp], erw [obj.map_on_summand₀ K A fac, obj.termwise.map_mono_id, id_comp, comp_id], unfreezingI { rcases A with ⟨Δ', ⟨...
def
algebraic_topology.dold_kan.Γ₀.obj
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "chain_complex" ]
The functor `Γ₀ : chain_complex C ℕ ⥤ simplicial_object C`, on objects.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
splitting_map_eq_id (Δ : simplex_categoryᵒᵖ) : (simplicial_object.splitting.map (Γ₀.obj K) (λ (n : ℕ), sigma.ι (Γ₀.obj.summand K (op [n])) (splitting.index_set.id (op [n]))) Δ) = 𝟙 _
begin ext A, discrete_cases, induction Δ using opposite.rec, induction Δ with n, dsimp, simp only [colimit.ι_desc, cofan.mk_ι_app, comp_id, Γ₀.obj_map], rw [Γ₀.obj.map_on_summand₀ K (simplicial_object.splitting.index_set.id A.1) (show A.e ≫ 𝟙 _ = A.e.op.unop ≫ 𝟙 _, by refl), Γ₀.obj.termwise.map_...
lemma
algebraic_topology.dold_kan.Γ₀.splitting_map_eq_id
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "opposite.rec", "simplicial_object.splitting.index_set.id", "simplicial_object.splitting.map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
splitting (K : chain_complex C ℕ) : simplicial_object.splitting (Γ₀.obj K)
{ N := λ n, K.X n, ι := λ n, sigma.ι (Γ₀.obj.summand K (op [n])) (splitting.index_set.id (op [n])), map_is_iso' := λ Δ, begin rw Γ₀.splitting_map_eq_id, apply is_iso.id, end, }
def
algebraic_topology.dold_kan.Γ₀.splitting
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "chain_complex", "simplicial_object.splitting" ]
By construction, the simplicial `Γ₀.obj K` is equipped with a splitting.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
splitting_iso_hom_eq_id (Δ : simplex_categoryᵒᵖ) : ((splitting K).iso Δ).hom = 𝟙 _
splitting_map_eq_id K Δ
lemma
algebraic_topology.dold_kan.Γ₀.splitting_iso_hom_eq_id
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
obj.map_on_summand {Δ Δ' : simplex_categoryᵒᵖ} (A : splitting.index_set Δ) (θ : Δ ⟶ Δ') {Δ'' : simplex_category} {e : Δ'.unop ⟶ Δ''} {i : Δ'' ⟶ A.1.unop} [epi e] [mono i] (fac : e ≫ i = θ.unop ≫ A.e) : (Γ₀.splitting K).ι_summand A ≫ (Γ₀.obj K).map θ = Γ₀.obj.termwise.map_mono K i ≫ (Γ₀.splitting K).ι_summand (s...
begin dsimp only [simplicial_object.splitting.ι_summand, simplicial_object.splitting.ι_coprod], simp only [assoc, Γ₀.splitting_iso_hom_eq_id, id_comp, comp_id], exact Γ₀.obj.map_on_summand₀ K A fac, end
lemma
algebraic_topology.dold_kan.Γ₀.obj.map_on_summand
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "simplex_category", "simplicial_object.splitting.ι_coprod", "simplicial_object.splitting.ι_summand" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
obj.map_on_summand' {Δ Δ' : simplex_categoryᵒᵖ} (A : splitting.index_set Δ) (θ : Δ ⟶ Δ') : (splitting K).ι_summand A ≫ (obj K).map θ = obj.termwise.map_mono K (image.ι (θ.unop ≫ A.e)) ≫ (splitting K).ι_summand (A.pull θ)
by { apply obj.map_on_summand, apply image.fac, }
lemma
algebraic_topology.dold_kan.Γ₀.obj.map_on_summand'
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
obj.map_mono_on_summand_id {Δ Δ' : simplex_category} (i : Δ' ⟶ Δ) [mono i] : (splitting K).ι_summand (splitting.index_set.id (op Δ)) ≫ (obj K).map i.op = obj.termwise.map_mono K i ≫ (splitting K).ι_summand (splitting.index_set.id (op Δ'))
obj.map_on_summand K (splitting.index_set.id (op Δ)) i.op (rfl : 𝟙 _ ≫ i = i ≫ 𝟙 _)
lemma
algebraic_topology.dold_kan.Γ₀.obj.map_mono_on_summand_id
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "simplex_category" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
obj.map_epi_on_summand_id {Δ Δ' : simplex_category } (e : Δ' ⟶ Δ) [epi e] : (Γ₀.splitting K).ι_summand (splitting.index_set.id (op Δ)) ≫ (Γ₀.obj K).map e.op = (Γ₀.splitting K).ι_summand (splitting.index_set.mk e)
by simpa only [Γ₀.obj.map_on_summand K (splitting.index_set.id (op Δ)) e.op (rfl : e ≫ 𝟙 Δ = e ≫ 𝟙 Δ), Γ₀.obj.termwise.map_mono_id] using id_comp _
lemma
algebraic_topology.dold_kan.Γ₀.obj.map_epi_on_summand_id
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "simplex_category" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map {K K' : chain_complex C ℕ} (f : K ⟶ K') : obj K ⟶ obj K'
{ app := λ Δ, (Γ₀.splitting K).desc Δ (λ A, f.f A.1.unop.len ≫ (Γ₀.splitting K').ι_summand A), naturality' := λ Δ' Δ θ, begin apply (Γ₀.splitting K).hom_ext', intro A, simp only [(splitting K).ι_desc_assoc, obj.map_on_summand'_assoc K _ θ, (splitting K).ι_desc, assoc, obj.map_on_summand' K' _ θ], ...
def
algebraic_topology.dold_kan.Γ₀.map
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "chain_complex" ]
The functor `Γ₀ : chain_complex C ℕ ⥤ simplicial_object C`, on morphisms.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Γ₀' : chain_complex C ℕ ⥤ simplicial_object.split C
{ obj := λ K, simplicial_object.split.mk' (Γ₀.splitting K), map := λ K K' f, { F := Γ₀.map f, f := f.f, comm' := λ n, by { dsimp, simpa only [← splitting.ι_summand_id, (Γ₀.splitting K).ι_desc], }, }, }
def
algebraic_topology.dold_kan.Γ₀'
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "chain_complex", "simplicial_object.split", "simplicial_object.split.mk'" ]
The functor `Γ₀' : chain_complex C ℕ ⥤ simplicial_object.split C` that induces `Γ₀ : chain_complex C ℕ ⥤ simplicial_object C`, which shall be the inverse functor of the Dold-Kan equivalence for abelian or pseudo-abelian categories.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Γ₀ : chain_complex C ℕ ⥤ simplicial_object C
Γ₀' ⋙ split.forget _
def
algebraic_topology.dold_kan.Γ₀
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "chain_complex" ]
The functor `Γ₀ : chain_complex C ℕ ⥤ simplicial_object C`, which is the inverse functor of the Dold-Kan equivalence when `C` is an abelian category, or more generally a pseudoabelian category.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Γ₂ : karoubi (chain_complex C ℕ) ⥤ karoubi (simplicial_object C)
(category_theory.idempotents.functor_extension₂ _ _).obj Γ₀
def
algebraic_topology.dold_kan.Γ₂
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "category_theory.idempotents.functor_extension₂", "chain_complex" ]
The extension of `Γ₀ : chain_complex C ℕ ⥤ simplicial_object C` on the idempotent completions. It shall be an equivalence of categories for any additive category `C`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
higher_faces_vanish.on_Γ₀_summand_id (K : chain_complex C ℕ) (n : ℕ) : higher_faces_vanish (n+1) ((Γ₀.splitting K).ι_summand (splitting.index_set.id (op [n+1])))
begin intros j hj, have eq := Γ₀.obj.map_mono_on_summand_id K (simplex_category.δ j.succ), rw [Γ₀.obj.termwise.map_mono_eq_zero K, zero_comp] at eq, rotate, { intro h, exact (nat.succ_ne_self n) (congr_arg simplex_category.len h), }, { exact λ h, fin.succ_ne_zero j (by simpa only [is_δ₀.iff] using h), }, ...
lemma
algebraic_topology.dold_kan.higher_faces_vanish.on_Γ₀_summand_id
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "chain_complex", "fin.succ_ne_zero", "simplex_category.len", "simplex_category.δ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
P_infty_on_Γ₀_splitting_summand_eq_self (K : chain_complex C ℕ) {n : ℕ} : (Γ₀.splitting K).ι_summand (splitting.index_set.id (op [n])) ≫ (P_infty : K[Γ₀.obj K] ⟶ _).f n = (Γ₀.splitting K).ι_summand (splitting.index_set.id (op [n]))
begin rw P_infty_f, cases n, { simpa only [P_f_0_eq] using comp_id _, }, { exact (higher_faces_vanish.on_Γ₀_summand_id K n).comp_P_eq_self, }, end
lemma
algebraic_topology.dold_kan.P_infty_on_Γ₀_splitting_summand_eq_self
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_gamma.lean
[ "algebraic_topology.dold_kan.split_simplicial_object" ]
[ "chain_complex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
N₁ : simplicial_object C ⥤ karoubi (chain_complex C ℕ)
{ obj := λ X, { X := alternating_face_map_complex.obj X, p := P_infty, idem := P_infty_idem, }, map := λ X Y f, { f := P_infty ≫ alternating_face_map_complex.map f, comm := by { ext, simp }, }, map_id' := λ X, by { ext, dsimp, simp }, map_comp' := λ X Y Z f g, by { ext, simp } }
def
algebraic_topology.dold_kan.N₁
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_n.lean
[ "algebraic_topology.dold_kan.p_infty" ]
[ "chain_complex", "comm" ]
The functor `simplicial_object C ⥤ karoubi (chain_complex C ℕ)` which maps `X` to the formal direct factor of `K[X]` defined by `P_infty`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
N₂ : karoubi (simplicial_object C) ⥤ karoubi (chain_complex C ℕ)
(functor_extension₁ _ _).obj N₁
def
algebraic_topology.dold_kan.N₂
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/functor_n.lean
[ "algebraic_topology.dold_kan.p_infty" ]
[ "chain_complex" ]
The extension of `N₁` to the Karoubi envelope of `simplicial_object C`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Γ₀_nondeg_complex_iso (K : chain_complex C ℕ) : (Γ₀.splitting K).nondeg_complex ≅ K
homological_complex.hom.iso_of_components (λ n, iso.refl _) begin rintros _ n (rfl : n+1=_), dsimp, simp only [id_comp, comp_id, alternating_face_map_complex.obj_d_eq, preadditive.sum_comp, preadditive.comp_sum], rw fintype.sum_eq_single (0 : fin (n+2)), { simp only [fin.coe_zero, pow_zero, one_zsmul], ...
def
algebraic_topology.dold_kan.Γ₀_nondeg_complex_iso
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/gamma_comp_n.lean
[ "algebraic_topology.dold_kan.functor_gamma", "category_theory.idempotents.homological_complex" ]
[ "chain_complex", "fin.coe_zero", "homological_complex.hom.iso_of_components", "pow_zero", "simplex_category.len" ]
The isomorphism `(Γ₀.splitting K).nondeg_complex ≅ K` for all `K : chain_complex C ℕ`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Γ₀'_comp_nondeg_complex_functor : Γ₀' ⋙ split.nondeg_complex_functor ≅ 𝟭 (chain_complex C ℕ)
nat_iso.of_components Γ₀_nondeg_complex_iso (λ X Y f, by { ext n, dsimp, simp only [comp_id, id_comp], })
def
algebraic_topology.dold_kan.Γ₀'_comp_nondeg_complex_functor
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/gamma_comp_n.lean
[ "algebraic_topology.dold_kan.functor_gamma", "category_theory.idempotents.homological_complex" ]
[ "chain_complex" ]
The natural isomorphism `(Γ₀.splitting K).nondeg_complex ≅ K` for `K : chain_complex C ℕ`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
N₁Γ₀ : Γ₀ ⋙ N₁ ≅ to_karoubi (chain_complex C ℕ)
calc Γ₀ ⋙ N₁ ≅ Γ₀' ⋙ split.forget C ⋙ N₁ : functor.associator _ _ _ ... ≅ Γ₀' ⋙ split.nondeg_complex_functor ⋙ to_karoubi _ : iso_whisker_left Γ₀' split.to_karoubi_nondeg_complex_functor_iso_N₁.symm ... ≅ (Γ₀' ⋙ split.nondeg_complex_functor) ⋙ to_karoubi _ : (functor.associator _ _ _).symm ... ≅ 𝟭 _ ⋙ to_karoubi (ch...
def
algebraic_topology.dold_kan.N₁Γ₀
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/gamma_comp_n.lean
[ "algebraic_topology.dold_kan.functor_gamma", "category_theory.idempotents.homological_complex" ]
[ "chain_complex" ]
The natural isomorphism `Γ₀ ⋙ N₁ ≅ to_karoubi (chain_complex C ℕ)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
N₁Γ₀_app (K : chain_complex C ℕ) : N₁Γ₀.app K = (Γ₀.splitting K).to_karoubi_nondeg_complex_iso_N₁.symm ≪≫ (to_karoubi _).map_iso (Γ₀_nondeg_complex_iso K)
begin ext1, dsimp [N₁Γ₀], erw [id_comp, comp_id, comp_id], refl, end
lemma
algebraic_topology.dold_kan.N₁Γ₀_app
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/gamma_comp_n.lean
[ "algebraic_topology.dold_kan.functor_gamma", "category_theory.idempotents.homological_complex" ]
[ "chain_complex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
N₁Γ₀_hom_app (K : chain_complex C ℕ) : N₁Γ₀.hom.app K = (Γ₀.splitting K).to_karoubi_nondeg_complex_iso_N₁.inv ≫ (to_karoubi _).map (Γ₀_nondeg_complex_iso K).hom
by { change (N₁Γ₀.app K).hom = _, simpa only [N₁Γ₀_app], }
lemma
algebraic_topology.dold_kan.N₁Γ₀_hom_app
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/gamma_comp_n.lean
[ "algebraic_topology.dold_kan.functor_gamma", "category_theory.idempotents.homological_complex" ]
[ "chain_complex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
N₁Γ₀_inv_app (K : chain_complex C ℕ) : N₁Γ₀.inv.app K = (to_karoubi _).map (Γ₀_nondeg_complex_iso K).inv ≫ (Γ₀.splitting K).to_karoubi_nondeg_complex_iso_N₁.hom
by { change (N₁Γ₀.app K).inv = _, simpa only [N₁Γ₀_app], }
lemma
algebraic_topology.dold_kan.N₁Γ₀_inv_app
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/gamma_comp_n.lean
[ "algebraic_topology.dold_kan.functor_gamma", "category_theory.idempotents.homological_complex" ]
[ "chain_complex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
N₁Γ₀_hom_app_f_f (K : chain_complex C ℕ) (n : ℕ) : (N₁Γ₀.hom.app K).f.f n = (Γ₀.splitting K).to_karoubi_nondeg_complex_iso_N₁.inv.f.f n
by { rw N₁Γ₀_hom_app, apply comp_id, }
lemma
algebraic_topology.dold_kan.N₁Γ₀_hom_app_f_f
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/gamma_comp_n.lean
[ "algebraic_topology.dold_kan.functor_gamma", "category_theory.idempotents.homological_complex" ]
[ "chain_complex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
N₁Γ₀_inv_app_f_f (K : chain_complex C ℕ) (n : ℕ) : (N₁Γ₀.inv.app K).f.f n = (Γ₀.splitting K).to_karoubi_nondeg_complex_iso_N₁.hom.f.f n
by { rw N₁Γ₀_inv_app, apply id_comp, }
lemma
algebraic_topology.dold_kan.N₁Γ₀_inv_app_f_f
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/gamma_comp_n.lean
[ "algebraic_topology.dold_kan.functor_gamma", "category_theory.idempotents.homological_complex" ]
[ "chain_complex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
N₂Γ₂_to_karoubi : to_karoubi (chain_complex C ℕ) ⋙ Γ₂ ⋙ N₂ = Γ₀ ⋙ N₁
begin have h := functor.congr_obj (functor_extension₂_comp_whiskering_left_to_karoubi (chain_complex C ℕ) (simplicial_object C)) Γ₀, have h' := functor.congr_obj (functor_extension₁_comp_whiskering_left_to_karoubi (simplicial_object C) (chain_complex C ℕ)) N₁, dsimp [N₂, Γ₂, functor_extension₁] at h h' ⊢,...
lemma
algebraic_topology.dold_kan.N₂Γ₂_to_karoubi
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/gamma_comp_n.lean
[ "algebraic_topology.dold_kan.functor_gamma", "category_theory.idempotents.homological_complex" ]
[ "chain_complex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
N₂Γ₂_to_karoubi_iso : to_karoubi (chain_complex C ℕ) ⋙ Γ₂ ⋙ N₂ ≅ Γ₀ ⋙ N₁
eq_to_iso (N₂Γ₂_to_karoubi)
def
algebraic_topology.dold_kan.N₂Γ₂_to_karoubi_iso
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/gamma_comp_n.lean
[ "algebraic_topology.dold_kan.functor_gamma", "category_theory.idempotents.homological_complex" ]
[ "chain_complex" ]
Compatibility isomorphism between `to_karoubi _ ⋙ Γ₂ ⋙ N₂` and `Γ₀ ⋙ N₁` which are functors `chain_complex C ℕ ⥤ karoubi (chain_complex C ℕ)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
N₂Γ₂ : Γ₂ ⋙ N₂ ≅ 𝟭 (karoubi (chain_complex C ℕ))
((whiskering_left _ _ _).obj (to_karoubi (chain_complex C ℕ))).preimage_iso (N₂Γ₂_to_karoubi_iso ≪≫ N₁Γ₀)
def
algebraic_topology.dold_kan.N₂Γ₂
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/gamma_comp_n.lean
[ "algebraic_topology.dold_kan.functor_gamma", "category_theory.idempotents.homological_complex" ]
[ "chain_complex" ]
The counit isomorphism of the Dold-Kan equivalence for additive categories.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
N₂Γ₂_compatible_with_N₁Γ₀ (K : chain_complex C ℕ) : N₂Γ₂.hom.app ((to_karoubi _).obj K) = N₂Γ₂_to_karoubi_iso.hom.app K ≫ N₁Γ₀.hom.app K
congr_app (((whiskering_left _ _ (karoubi (chain_complex C ℕ ))).obj (to_karoubi (chain_complex C ℕ))).image_preimage (N₂Γ₂_to_karoubi_iso.hom ≫ N₁Γ₀.hom : _ ⟶ to_karoubi _ ⋙ 𝟭 _)) K
lemma
algebraic_topology.dold_kan.N₂Γ₂_compatible_with_N₁Γ₀
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/gamma_comp_n.lean
[ "algebraic_topology.dold_kan.functor_gamma", "category_theory.idempotents.homological_complex" ]
[ "chain_complex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
N₂Γ₂_inv_app_f_f (X : karoubi (chain_complex C ℕ)) (n : ℕ) : (N₂Γ₂.inv.app X).f.f n = X.p.f n ≫ (Γ₀.splitting X.X).ι_summand (splitting.index_set.id (op [n]))
begin dsimp only [N₂Γ₂, functor.preimage_iso, iso.trans], simp only [whiskering_left_obj_preimage_app, N₂Γ₂_to_karoubi_iso_inv, functor.id_map, nat_trans.comp_app, eq_to_hom_app, functor.comp_map, assoc, karoubi.comp_f, karoubi.eq_to_hom_f, eq_to_hom_refl, comp_id, karoubi.comp_p_assoc, N₂_map_f_f, homo...
lemma
algebraic_topology.dold_kan.N₂Γ₂_inv_app_f_f
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/gamma_comp_n.lean
[ "algebraic_topology.dold_kan.functor_gamma", "category_theory.idempotents.homological_complex" ]
[ "chain_complex", "homological_complex.comp_f" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
c
complex_shape.down ℕ
abbreviation
algebraic_topology.dold_kan.c
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopies.lean
[ "algebra.homology.homotopy", "algebraic_topology.dold_kan.notations" ]
[ "complex_shape.down" ]
As we are using chain complexes indexed by `ℕ`, we shall need the relation `c` such `c m n` if and only if `n+1=m`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
c_mk (i j : ℕ) (h : j+1 = i) : c.rel i j
complex_shape.down_mk i j h
lemma
algebraic_topology.dold_kan.c_mk
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopies.lean
[ "algebra.homology.homotopy", "algebraic_topology.dold_kan.notations" ]
[ "complex_shape.down_mk" ]
Helper when we need some `c.rel i j` (i.e. `complex_shape.down ℕ`), e.g. `c_mk n (n+1) rfl`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cs_down_0_not_rel_left (j : ℕ) : ¬c.rel 0 j
begin intro hj, dsimp at hj, apply nat.not_succ_le_zero j, rw [nat.succ_eq_add_one, hj], end
lemma
algebraic_topology.dold_kan.cs_down_0_not_rel_left
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopies.lean
[ "algebra.homology.homotopy", "algebraic_topology.dold_kan.notations" ]
[]
This lemma is meant to be used with `null_homotopic_map'_f_of_not_rel_left`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hσ (q : ℕ) (n : ℕ) : X _[n] ⟶ X _[n+1]
if n<q then 0 else (-1 : ℤ)^(n-q) • X.σ ⟨n-q, nat.sub_lt_succ n q⟩
def
algebraic_topology.dold_kan.hσ
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopies.lean
[ "algebra.homology.homotopy", "algebraic_topology.dold_kan.notations" ]
[]
The sequence of maps which gives the null homotopic maps `Hσ` that shall be in the inductive construction of the projections `P q : K[X] ⟶ K[X]`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hσ' (q : ℕ) : Π n m, c.rel m n → (K[X].X n ⟶ K[X].X m)
λ n m hnm, (hσ q n) ≫ eq_to_hom (by congr')
def
algebraic_topology.dold_kan.hσ'
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopies.lean
[ "algebra.homology.homotopy", "algebraic_topology.dold_kan.notations" ]
[]
We can turn `hσ` into a datum that can be passed to `null_homotopic_map'`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hσ'_eq_zero {q n m : ℕ} (hnq : n<q) (hnm : c.rel m n) : (hσ' q n m hnm : X _[n] ⟶ X _[m])= 0
by { simp only [hσ', hσ], split_ifs, exact zero_comp, }
lemma
algebraic_topology.dold_kan.hσ'_eq_zero
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopies.lean
[ "algebra.homology.homotopy", "algebraic_topology.dold_kan.notations" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hσ'_eq {q n a m : ℕ} (ha : n=a+q) (hnm : c.rel m n) : (hσ' q n m hnm : X _[n] ⟶ X _[m]) = ((-1 : ℤ)^a • X.σ ⟨a, nat.lt_succ_iff.mpr (nat.le.intro (eq.symm ha))⟩) ≫ eq_to_hom (by congr')
begin simp only [hσ', hσ], split_ifs, { exfalso, linarith, }, { have h' := tsub_eq_of_eq_add ha, congr', } end
lemma
algebraic_topology.dold_kan.hσ'_eq
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopies.lean
[ "algebra.homology.homotopy", "algebraic_topology.dold_kan.notations" ]
[ "tsub_eq_of_eq_add" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hσ'_eq' {q n a : ℕ} (ha : n=a+q) : (hσ' q n (n+1) rfl : X _[n] ⟶ X _[n+1]) = (-1 : ℤ)^a • X.σ ⟨a, nat.lt_succ_iff.mpr (nat.le.intro (eq.symm ha))⟩
by rw [hσ'_eq ha rfl, eq_to_hom_refl, comp_id]
lemma
algebraic_topology.dold_kan.hσ'_eq'
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopies.lean
[ "algebra.homology.homotopy", "algebraic_topology.dold_kan.notations" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Hσ (q : ℕ) : K[X] ⟶ K[X]
null_homotopic_map' (hσ' q)
def
algebraic_topology.dold_kan.Hσ
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopies.lean
[ "algebra.homology.homotopy", "algebraic_topology.dold_kan.notations" ]
[]
The null homotopic map $(hσ q) ∘ d + d ∘ (hσ q)$
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homotopy_Hσ_to_zero (q : ℕ) : homotopy (Hσ q : K[X] ⟶ K[X]) 0
null_homotopy' (hσ' q)
def
algebraic_topology.dold_kan.homotopy_Hσ_to_zero
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopies.lean
[ "algebra.homology.homotopy", "algebraic_topology.dold_kan.notations" ]
[ "homotopy" ]
`Hσ` is null homotopic
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Hσ_eq_zero (q : ℕ) : (Hσ q : K[X] ⟶ K[X]).f 0 = 0
begin unfold Hσ, rw null_homotopic_map'_f_of_not_rel_left (c_mk 1 0 rfl) cs_down_0_not_rel_left, cases q, { rw hσ'_eq (show 0=0+0, by refl) (c_mk 1 0 rfl), simp only [pow_zero, fin.mk_zero, one_zsmul, eq_to_hom_refl, category.comp_id], erw chain_complex.of_d, simp only [alternating_face_map_complex....
lemma
algebraic_topology.dold_kan.Hσ_eq_zero
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopies.lean
[ "algebra.homology.homotopy", "algebraic_topology.dold_kan.notations" ]
[ "chain_complex.of_d", "fin.coe_one", "fin.coe_zero", "fin.mk_zero", "neg_smul", "pow_one", "pow_zero" ]
In degree `0`, the null homotopic map `Hσ` is zero.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hσ'_naturality (q : ℕ) (n m : ℕ) (hnm : c.rel m n) {X Y : simplicial_object C} (f : X ⟶ Y) : f.app (op [n]) ≫ hσ' q n m hnm = hσ' q n m hnm ≫ f.app (op [m])
begin have h : n+1 = m := hnm, subst h, simp only [hσ', eq_to_hom_refl, comp_id], unfold hσ, split_ifs, { rw [zero_comp, comp_zero], }, { simp only [zsmul_comp, comp_zsmul], erw f.naturality, refl, }, end
lemma
algebraic_topology.dold_kan.hσ'_naturality
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopies.lean
[ "algebra.homology.homotopy", "algebraic_topology.dold_kan.notations" ]
[]
The maps `hσ' q n m hnm` are natural on the simplicial object
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_trans_Hσ (q : ℕ) : alternating_face_map_complex C ⟶ alternating_face_map_complex C
{ app := λ X, Hσ q, naturality' := λ X Y f, begin unfold Hσ, rw [null_homotopic_map'_comp, comp_null_homotopic_map'], congr, ext n m hnm, simp only [alternating_face_map_complex_map_f, hσ'_naturality], end, }
def
algebraic_topology.dold_kan.nat_trans_Hσ
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopies.lean
[ "algebra.homology.homotopy", "algebraic_topology.dold_kan.notations" ]
[]
For each q, `Hσ q` is a natural transformation.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_hσ' {D : Type*} [category D] [preadditive D] (G : C ⥤ D) [G.additive] (X : simplicial_object C) (q n m : ℕ) (hnm : c.rel m n) : (hσ' q n m hnm : K[((whiskering _ _).obj G).obj X].X n ⟶ _) = G.map (hσ' q n m hnm : K[X].X n ⟶ _)
begin unfold hσ' hσ, split_ifs, { simp only [functor.map_zero, zero_comp], }, { simpa only [eq_to_hom_map, functor.map_comp, functor.map_zsmul], }, end
lemma
algebraic_topology.dold_kan.map_hσ'
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopies.lean
[ "algebra.homology.homotopy", "algebraic_topology.dold_kan.notations" ]
[]
The maps `hσ' q n m hnm` are compatible with the application of additive functors.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_Hσ {D : Type*} [category D] [preadditive D] (G : C ⥤ D) [G.additive] (X : simplicial_object C) (q n : ℕ) : (Hσ q : K[((whiskering C D).obj G).obj X] ⟶ _).f n = G.map ((Hσ q : K[X] ⟶ _).f n)
begin unfold Hσ, have eq := homological_complex.congr_hom (map_null_homotopic_map' G (hσ' q)) n, simp only [functor.map_homological_complex_map_f, ← map_hσ'] at eq, rw eq, let h := (functor.congr_obj (map_alternating_face_map_complex G) X).symm, congr', end
lemma
algebraic_topology.dold_kan.map_Hσ
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopies.lean
[ "algebra.homology.homotopy", "algebraic_topology.dold_kan.notations" ]
[ "homological_complex.congr_hom" ]
The null homotopic maps `Hσ` are compatible with the application of additive functors.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homotopy_P_to_id : Π (q : ℕ), homotopy (P q : K[X] ⟶ _) (𝟙 _)
| 0 := homotopy.refl _ | (q+1) := begin refine homotopy.trans (homotopy.of_eq _) (homotopy.trans (homotopy.add (homotopy_P_to_id q) (homotopy.comp_left (homotopy_Hσ_to_zero q) (P q))) (homotopy.of_eq _)), { unfold P, simp only [comp_add, comp_id], }, { simp only [add_zero, comp_zer...
def
algebraic_topology.dold_kan.homotopy_P_to_id
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopy_equivalence.lean
[ "algebraic_topology.dold_kan.normalized" ]
[ "homotopy", "homotopy.add", "homotopy.comp_left", "homotopy.of_eq", "homotopy.refl", "homotopy.trans" ]
Inductive construction of homotopies from `P q` to `𝟙 _`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homotopy_Q_to_zero (q : ℕ) : homotopy (Q q : K[X] ⟶ _) 0
homotopy.equiv_sub_zero.to_fun (homotopy_P_to_id X q).symm
def
algebraic_topology.dold_kan.homotopy_Q_to_zero
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopy_equivalence.lean
[ "algebraic_topology.dold_kan.normalized" ]
[ "homotopy" ]
The complement projection `Q q` to `P q` is homotopic to zero.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homotopy_P_to_id_eventually_constant {q n : ℕ} (hqn : n<q): ((homotopy_P_to_id X (q+1)).hom n (n+1) : X _[n] ⟶ X _[n+1]) = (homotopy_P_to_id X q).hom n (n+1)
begin unfold homotopy_P_to_id, simp only [homotopy_Hσ_to_zero, hσ'_eq_zero hqn (c_mk (n+1) n rfl), homotopy.trans_hom, pi.add_apply, homotopy.of_eq_hom, pi.zero_apply, homotopy.add_hom, homotopy.comp_left_hom, homotopy.null_homotopy'_hom, complex_shape.down_rel, eq_self_iff_true, dite_eq_ite, if_true, c...
lemma
algebraic_topology.dold_kan.homotopy_P_to_id_eventually_constant
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopy_equivalence.lean
[ "algebraic_topology.dold_kan.normalized" ]
[ "dite_eq_ite" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homotopy_P_infty_to_id : homotopy (P_infty : K[X] ⟶ _) (𝟙 _)
{ hom := λ i j, (homotopy_P_to_id X (j+1)).hom i j, zero' := λ i j hij, homotopy.zero _ i j hij, comm := λ n, begin cases n, { simpa only [homotopy.d_next_zero_chain_complex, homotopy.prev_d_chain_complex, P_f_0_eq, zero_add, homological_complex.id_f, P_infty_f] using (homotopy_P_to_id X 2).comm 0,...
def
algebraic_topology.dold_kan.homotopy_P_infty_to_id
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopy_equivalence.lean
[ "algebraic_topology.dold_kan.normalized" ]
[ "comm", "homological_complex.id_f", "homotopy", "homotopy.d_next_succ_chain_complex", "homotopy.d_next_zero_chain_complex", "homotopy.prev_d_chain_complex", "lt_add_one" ]
Construction of the homotopy from `P_infty` to the identity using eventually (termwise) constant homotopies from `P q` to the identity for all `q`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homotopy_equiv_normalized_Moore_complex_alternating_face_map_complex {A : Type*} [category A] [abelian A] {Y : simplicial_object A} : homotopy_equiv ((normalized_Moore_complex A).obj Y) ((alternating_face_map_complex A).obj Y)
{ hom := inclusion_of_Moore_complex_map Y, inv := P_infty_to_normalized_Moore_complex Y, homotopy_hom_inv_id := homotopy.of_eq (split_mono_inclusion_of_Moore_complex_map Y).id, homotopy_inv_hom_id := homotopy.trans (homotopy.of_eq (P_infty_to_normalized_Moore_complex_comp_inclusion_of_Moore_complex_map Y)) ...
def
algebraic_topology.dold_kan.homotopy_equiv_normalized_Moore_complex_alternating_face_map_complex
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/homotopy_equivalence.lean
[ "algebraic_topology.dold_kan.normalized" ]
[ "homotopy.of_eq", "homotopy.trans", "homotopy_equiv" ]
The inclusion of the Moore complex in the alternating face map complex is an homotopy equivalence
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
higher_faces_vanish.inclusion_of_Moore_complex_map (n : ℕ) : higher_faces_vanish (n+1) ((inclusion_of_Moore_complex_map X).f (n+1))
λ j hj, begin dsimp [inclusion_of_Moore_complex_map], rw [← factor_thru_arrow _ _ (finset_inf_arrow_factors finset.univ _ j (by simp only [finset.mem_univ])), assoc, kernel_subobject_arrow_comp, comp_zero], end
lemma
algebraic_topology.dold_kan.higher_faces_vanish.inclusion_of_Moore_complex_map
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/normalized.lean
[ "algebraic_topology.dold_kan.functor_n" ]
[ "finset.mem_univ", "finset.univ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
factors_normalized_Moore_complex_P_infty (n : ℕ) : subobject.factors (normalized_Moore_complex.obj_X X n) (P_infty.f n)
begin cases n, { apply top_factors, }, { rw [P_infty_f, normalized_Moore_complex.obj_X, finset_inf_factors], intros i hi, apply kernel_subobject_factors, exact (higher_faces_vanish.of_P (n+1) n) i (le_add_self), } end
lemma
algebraic_topology.dold_kan.factors_normalized_Moore_complex_P_infty
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/normalized.lean
[ "algebraic_topology.dold_kan.functor_n" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
P_infty_to_normalized_Moore_complex (X : simplicial_object A) : K[X] ⟶ N[X]
chain_complex.of_hom _ _ _ _ _ _ (λ n, factor_thru _ _ (factors_normalized_Moore_complex_P_infty n)) (λ n, begin rw [← cancel_mono (normalized_Moore_complex.obj_X X n).arrow, assoc, assoc, factor_thru_arrow, ← inclusion_of_Moore_complex_map_f, ← normalized_Moore_complex_obj_d, ← (inclusion_of_Moore_...
def
algebraic_topology.dold_kan.P_infty_to_normalized_Moore_complex
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/normalized.lean
[ "algebraic_topology.dold_kan.functor_n" ]
[ "chain_complex.of_hom" ]
P_infty factors through the normalized Moore complex
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
P_infty_to_normalized_Moore_complex_comp_inclusion_of_Moore_complex_map (X : simplicial_object A) : P_infty_to_normalized_Moore_complex X ≫ inclusion_of_Moore_complex_map X = P_infty
by tidy
lemma
algebraic_topology.dold_kan.P_infty_to_normalized_Moore_complex_comp_inclusion_of_Moore_complex_map
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/normalized.lean
[ "algebraic_topology.dold_kan.functor_n" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
P_infty_to_normalized_Moore_complex_naturality {X Y : simplicial_object A} (f : X ⟶ Y) : alternating_face_map_complex.map f ≫ P_infty_to_normalized_Moore_complex Y = P_infty_to_normalized_Moore_complex X ≫ normalized_Moore_complex.map f
by tidy
lemma
algebraic_topology.dold_kan.P_infty_to_normalized_Moore_complex_naturality
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/normalized.lean
[ "algebraic_topology.dold_kan.functor_n" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
P_infty_comp_P_infty_to_normalized_Moore_complex (X : simplicial_object A) : P_infty ≫ P_infty_to_normalized_Moore_complex X = P_infty_to_normalized_Moore_complex X
by tidy
lemma
algebraic_topology.dold_kan.P_infty_comp_P_infty_to_normalized_Moore_complex
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/normalized.lean
[ "algebraic_topology.dold_kan.functor_n" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inclusion_of_Moore_complex_map_comp_P_infty (X : simplicial_object A) : inclusion_of_Moore_complex_map X ≫ P_infty = inclusion_of_Moore_complex_map X
begin ext n, cases n, { dsimp, simp only [comp_id], }, { exact (higher_faces_vanish.inclusion_of_Moore_complex_map n).comp_P_eq_self, }, end
lemma
algebraic_topology.dold_kan.inclusion_of_Moore_complex_map_comp_P_infty
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/normalized.lean
[ "algebraic_topology.dold_kan.functor_n" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
split_mono_inclusion_of_Moore_complex_map (X : simplicial_object A) : split_mono (inclusion_of_Moore_complex_map X)
{ retraction := P_infty_to_normalized_Moore_complex X, id' := by simp only [← cancel_mono (inclusion_of_Moore_complex_map X), assoc, id_comp, P_infty_to_normalized_Moore_complex_comp_inclusion_of_Moore_complex_map, inclusion_of_Moore_complex_map_comp_P_infty], }
def
algebraic_topology.dold_kan.split_mono_inclusion_of_Moore_complex_map
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/normalized.lean
[ "algebraic_topology.dold_kan.functor_n" ]
[]
`inclusion_of_Moore_complex_map X` is a split mono.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
N₁_iso_normalized_Moore_complex_comp_to_karoubi : N₁ ≅ (normalized_Moore_complex A ⋙ to_karoubi _)
{ hom := { app := λ X, { f := P_infty_to_normalized_Moore_complex X, comm := by erw [comp_id, P_infty_comp_P_infty_to_normalized_Moore_complex] }, naturality' := λ X Y f, by simp only [functor.comp_map, normalized_Moore_complex_map, P_infty_to_normalized_Moore_complex_naturality, karoubi.hom_ext, ...
def
algebraic_topology.dold_kan.N₁_iso_normalized_Moore_complex_comp_to_karoubi
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/normalized.lean
[ "algebraic_topology.dold_kan.functor_n" ]
[ "comm", "homological_complex.comp_f" ]
When the category `A` is abelian, the functor `N₁ : simplicial_object A ⥤ karoubi (chain_complex A ℕ)` defined using `P_infty` identifies to the composition of the normalized Moore complex functor and the inclusion in the Karoubi envelope.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
P_infty_comp_map_mono_eq_zero (X : simplicial_object C) {n : ℕ} {Δ' : simplex_category} (i : Δ' ⟶ [n]) [hi : mono i] (h₁ : Δ'.len ≠ n) (h₂ : ¬is_δ₀ i) : P_infty.f n ≫ X.map i.op = 0
begin unfreezingI { induction Δ' using simplex_category.rec with m, }, obtain ⟨k, hk⟩ := nat.exists_eq_add_of_lt (len_lt_of_mono i (λ h, by { rw ← h at h₁, exact h₁ rfl, })), simp only [len_mk] at hk, cases k, { change n = m + 1 at hk, unfreezingI { subst hk, obtain ⟨j, rfl⟩ := eq_δ_of_mono i, }, ...
lemma
algebraic_topology.dold_kan.P_infty_comp_map_mono_eq_zero
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/n_comp_gamma.lean
[ "algebraic_topology.dold_kan.gamma_comp_n", "algebraic_topology.dold_kan.n_reflects_iso" ]
[ "by_contra", "fin.coe_succ", "fin.coe_zero", "fin.ext_iff", "fin.zero_le", "nat.exists_eq_add_of_lt", "nat.lt_one_iff", "simplex_category", "simplex_category.rec", "simplex_category.δ_comp_δ''" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Γ₀_obj_termwise_map_mono_comp_P_infty (X : simplicial_object C) {Δ Δ' : simplex_category} (i : Δ ⟶ Δ') [mono i] : Γ₀.obj.termwise.map_mono (alternating_face_map_complex.obj X) i ≫ P_infty.f (Δ.len) = P_infty.f (Δ'.len) ≫ X.map i.op
begin unfreezingI { induction Δ using simplex_category.rec with n, induction Δ' using simplex_category.rec with n', }, dsimp, /- We start with the case `i` is an identity -/ by_cases n = n', { unfreezingI { subst h, }, simp only [simplex_category.eq_id_of_mono i, Γ₀.obj.termwise.map_mono_id, op_id, ...
lemma
algebraic_topology.dold_kan.Γ₀_obj_termwise_map_mono_comp_P_infty
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/n_comp_gamma.lean
[ "algebraic_topology.dold_kan.gamma_comp_n", "algebraic_topology.dold_kan.n_reflects_iso" ]
[ "by_contradiction", "fin.coe_zero", "finset.mem_univ", "is_empty.forall_iff", "pow_zero", "simplex_category", "simplex_category.eq_id_of_mono", "simplex_category.len", "simplex_category.rec", "simplex_category.δ" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_trans : (N₁ : simplicial_object C ⥤ _) ⋙ Γ₂ ⟶ to_karoubi _
{ app := λ X, { f := { app := λ Δ, (Γ₀.splitting K[X]).desc Δ (λ A, P_infty.f A.1.unop.len ≫ X.map (A.e.op)), naturality' := λ Δ Δ' θ, begin apply (Γ₀.splitting K[X]).hom_ext', intro A, change _ ≫ (Γ₀.obj K[X]).map θ ≫ _ = _, simp only [splitting.ι_desc_assoc, assoc, ...
def
algebraic_topology.dold_kan.Γ₂N₁.nat_trans
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/n_comp_gamma.lean
[ "algebraic_topology.dold_kan.gamma_comp_n", "algebraic_topology.dold_kan.n_reflects_iso" ]
[ "comm", "hom_ext", "homological_complex.comp_f", "quiver.hom.unop_inj" ]
The natural transformation `N₁ ⋙ Γ₂ ⟶ to_karoubi (simplicial_object C)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
compatibility_Γ₂N₁_Γ₂N₂ : to_karoubi (simplicial_object C) ⋙ N₂ ⋙ Γ₂ ≅ N₁ ⋙ Γ₂
eq_to_iso (functor.congr_obj (functor_extension₁_comp_whiskering_left_to_karoubi _ _) (N₁ ⋙ Γ₂))
def
algebraic_topology.dold_kan.compatibility_Γ₂N₁_Γ₂N₂
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/n_comp_gamma.lean
[ "algebraic_topology.dold_kan.gamma_comp_n", "algebraic_topology.dold_kan.n_reflects_iso" ]
[]
The compatibility isomorphism relating `N₂ ⋙ Γ₂` and `N₁ ⋙ Γ₂`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_trans : (N₂ : karoubi (simplicial_object C) ⥤ _) ⋙ Γ₂ ⟶ 𝟭 _
((whiskering_left _ _ _).obj _).preimage (compatibility_Γ₂N₁_Γ₂N₂.hom ≫ Γ₂N₁.nat_trans)
def
algebraic_topology.dold_kan.Γ₂N₂.nat_trans
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/n_comp_gamma.lean
[ "algebraic_topology.dold_kan.gamma_comp_n", "algebraic_topology.dold_kan.n_reflects_iso" ]
[]
The natural transformation `N₂ ⋙ Γ₂ ⟶ 𝟭 (simplicial_object C)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_trans_app_f_app (P : karoubi (simplicial_object C)) : Γ₂N₂.nat_trans.app P = (N₂ ⋙ Γ₂).map P.decomp_id_i ≫ (compatibility_Γ₂N₁_Γ₂N₂.hom ≫ Γ₂N₁.nat_trans).app P.X ≫ P.decomp_id_p
whiskering_left_obj_preimage_app ((compatibility_Γ₂N₁_Γ₂N₂.hom ≫ Γ₂N₁.nat_trans)) P
lemma
algebraic_topology.dold_kan.Γ₂N₂.nat_trans_app_f_app
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/n_comp_gamma.lean
[ "algebraic_topology.dold_kan.gamma_comp_n", "algebraic_topology.dold_kan.n_reflects_iso" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
compatibility_Γ₂N₁_Γ₂N₂_nat_trans (X : simplicial_object C) : Γ₂N₁.nat_trans.app X = (compatibility_Γ₂N₁_Γ₂N₂.app X).inv ≫ Γ₂N₂.nat_trans.app ((to_karoubi _).obj X)
begin rw [← cancel_epi (compatibility_Γ₂N₁_Γ₂N₂.app X).hom, iso.hom_inv_id_assoc], exact congr_app (((whiskering_left _ _ _).obj _).image_preimage (compatibility_Γ₂N₁_Γ₂N₂.hom ≫ Γ₂N₁.nat_trans : _ ⟶ to_karoubi _ ⋙ 𝟭 _ )).symm X, end
lemma
algebraic_topology.dold_kan.compatibility_Γ₂N₁_Γ₂N₂_nat_trans
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/n_comp_gamma.lean
[ "algebraic_topology.dold_kan.gamma_comp_n", "algebraic_topology.dold_kan.n_reflects_iso" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
identity_N₂_objectwise (P : karoubi (simplicial_object C)) : N₂Γ₂.inv.app (N₂.obj P) ≫ N₂.map (Γ₂N₂.nat_trans.app P) = 𝟙 (N₂.obj P)
begin ext n, have eq₁ : (N₂Γ₂.inv.app (N₂.obj P)).f.f n = P_infty.f n ≫ P.p.app (op [n]) ≫ (Γ₀.splitting (N₂.obj P).X).ι_summand (splitting.index_set.id (op [n])), { simp only [N₂Γ₂_inv_app_f_f, N₂_obj_p_f, assoc], }, have eq₂ : (Γ₀.splitting (N₂.obj P).X).ι_summand (splitting.index_set.id (op [n])) ≫ (...
lemma
algebraic_topology.dold_kan.identity_N₂_objectwise
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/n_comp_gamma.lean
[ "algebraic_topology.dold_kan.gamma_comp_n", "algebraic_topology.dold_kan.n_reflects_iso" ]
[ "homological_complex.comp_f" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
identity_N₂ : ((𝟙 (N₂ : karoubi (simplicial_object C) ⥤ _ ) ◫ N₂Γ₂.inv) ≫ (Γ₂N₂.nat_trans ◫ 𝟙 N₂) : N₂ ⟶ N₂) = 𝟙 N₂
by { ext P : 2, dsimp, rw [Γ₂.map_id, N₂.map_id, comp_id, id_comp, identity_N₂_objectwise P], }
lemma
algebraic_topology.dold_kan.identity_N₂
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/n_comp_gamma.lean
[ "algebraic_topology.dold_kan.gamma_comp_n", "algebraic_topology.dold_kan.n_reflects_iso" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Γ₂N₂ : 𝟭 _ ≅ (N₂ : karoubi (simplicial_object C) ⥤ _) ⋙ Γ₂
(as_iso Γ₂N₂.nat_trans).symm
def
algebraic_topology.dold_kan.Γ₂N₂
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/n_comp_gamma.lean
[ "algebraic_topology.dold_kan.gamma_comp_n", "algebraic_topology.dold_kan.n_reflects_iso" ]
[]
The unit isomorphism of the Dold-Kan equivalence.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Γ₂N₁ : to_karoubi _ ≅ (N₁ : simplicial_object C ⥤ _) ⋙ Γ₂
(as_iso Γ₂N₁.nat_trans).symm
def
algebraic_topology.dold_kan.Γ₂N₁
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/n_comp_gamma.lean
[ "algebraic_topology.dold_kan.gamma_comp_n", "algebraic_topology.dold_kan.n_reflects_iso" ]
[]
The natural isomorphism `to_karoubi (simplicial_object C) ≅ N₁ ⋙ Γ₂`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
compatibility_N₂_N₁_karoubi : N₂ ⋙ (karoubi_chain_complex_equivalence C ℕ).functor = karoubi_functor_category_embedding simplex_categoryᵒᵖ C ⋙ N₁ ⋙ (karoubi_chain_complex_equivalence (karoubi C) ℕ).functor ⋙ functor.map_homological_complex (karoubi_karoubi.equivalence C).inverse _
begin refine category_theory.functor.ext (λ P, _) (λ P Q f, _), { refine homological_complex.ext _ _, { ext n, { dsimp, simp only [karoubi_P_infty_f, comp_id, P_infty_f_naturality, id_comp], }, { refl, }, }, { rintros _ n (rfl : n+1 = _), ext, have h := (alternating_face_map_...
lemma
algebraic_topology.dold_kan.compatibility_N₂_N₁_karoubi
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/n_reflects_iso.lean
[ "algebraic_topology.dold_kan.functor_n", "algebraic_topology.dold_kan.decomposition", "category_theory.idempotents.homological_complex", "category_theory.idempotents.karoubi_karoubi" ]
[ "category_theory.functor.ext", "comm", "homological_complex.eq_to_hom_f", "homological_complex.ext" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
P : ℕ → (K[X] ⟶ K[X])
| 0 := 𝟙 _ | (q+1) := P q ≫ (𝟙 _ + Hσ q)
def
algebraic_topology.dold_kan.P
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/projections.lean
[ "algebraic_topology.dold_kan.faces", "category_theory.idempotents.basic" ]
[]
This is the inductive definition of the projections `P q : K[X] ⟶ K[X]`, with `P 0 := 𝟙 _` and `P (q+1) := P q ≫ (𝟙 _ + Hσ q)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
P_f_0_eq (q : ℕ) : ((P q).f 0 : X _[0] ⟶ X _[0]) = 𝟙 _
begin induction q with q hq, { refl, }, { unfold P, simp only [homological_complex.add_f_apply, homological_complex.comp_f, homological_complex.id_f, id_comp, hq, Hσ_eq_zero, add_zero], }, end
lemma
algebraic_topology.dold_kan.P_f_0_eq
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/projections.lean
[ "algebraic_topology.dold_kan.faces", "category_theory.idempotents.basic" ]
[ "homological_complex.add_f_apply", "homological_complex.comp_f", "homological_complex.id_f" ]
All the `P q` coincide with `𝟙 _` in degree 0.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Q (q : ℕ) : K[X] ⟶ K[X]
𝟙 _ - P q
def
algebraic_topology.dold_kan.Q
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/projections.lean
[ "algebraic_topology.dold_kan.faces", "category_theory.idempotents.basic" ]
[]
`Q q` is the complement projection associated to `P q`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
P_add_Q (q : ℕ) : P q + Q q = 𝟙 K[X]
by { rw Q, abel, }
lemma
algebraic_topology.dold_kan.P_add_Q
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/projections.lean
[ "algebraic_topology.dold_kan.faces", "category_theory.idempotents.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
P_add_Q_f (q n : ℕ) : (P q).f n + (Q q).f n = 𝟙 (X _[n])
homological_complex.congr_hom (P_add_Q q) n
lemma
algebraic_topology.dold_kan.P_add_Q_f
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/projections.lean
[ "algebraic_topology.dold_kan.faces", "category_theory.idempotents.basic" ]
[ "homological_complex.congr_hom" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Q_eq_zero : (Q 0 : K[X] ⟶ _) = 0
sub_self _
lemma
algebraic_topology.dold_kan.Q_eq_zero
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/projections.lean
[ "algebraic_topology.dold_kan.faces", "category_theory.idempotents.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Q_eq (q : ℕ) : (Q (q+1) : K[X] ⟶ _) = Q q - P q ≫ Hσ q
by { unfold Q P, simp only [comp_add, comp_id], abel, }
lemma
algebraic_topology.dold_kan.Q_eq
algebraic_topology.dold_kan
src/algebraic_topology/dold_kan/projections.lean
[ "algebraic_topology.dold_kan.faces", "category_theory.idempotents.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83