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desc_f_one {Y Z : C} (f : Z ⟶ Y) (I : InjectiveResolution Y) (J : InjectiveResolution Z) : J.cocomplex.X 1 ⟶ I.cocomplex.X 1
exact.desc (desc_f_zero f I J ≫ I.cocomplex.d 0 1) (J.ι.f 0) (J.cocomplex.d 0 1) (abelian.exact.op _ _ J.exact₀) (by simp [←category.assoc, desc_f_zero])
def
category_theory.InjectiveResolution.desc_f_one
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[]
Auxiliary construction for `desc`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
desc_f_one_zero_comm {Y Z : C} (f : Z ⟶ Y) (I : InjectiveResolution Y) (J : InjectiveResolution Z) : J.cocomplex.d 0 1 ≫ desc_f_one f I J = desc_f_zero f I J ≫ I.cocomplex.d 0 1
by simp [desc_f_zero, desc_f_one]
lemma
category_theory.InjectiveResolution.desc_f_one_zero_comm
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
desc_f_succ {Y Z : C} (I : InjectiveResolution Y) (J : InjectiveResolution Z) (n : ℕ) (g : J.cocomplex.X n ⟶ I.cocomplex.X n) (g' : J.cocomplex.X (n+1) ⟶ I.cocomplex.X (n+1)) (w : J.cocomplex.d n (n+1) ≫ g' = g ≫ I.cocomplex.d n (n+1)) : Σ' g'' : J.cocomplex.X (n+2) ⟶ I.cocomplex.X (n+2), J.cocomplex.d (n+1...
⟨@exact.desc C _ _ _ _ _ _ _ _ _ (g' ≫ I.cocomplex.d (n+1) (n+2)) (J.cocomplex.d n (n+1)) (J.cocomplex.d (n+1) (n+2)) (abelian.exact.op _ _ (J.exact _)) (by simp [←category.assoc, w]), (by simp)⟩
def
category_theory.InjectiveResolution.desc_f_succ
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[]
Auxiliary construction for `desc`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
desc {Y Z : C} (f : Z ⟶ Y) (I : InjectiveResolution Y) (J : InjectiveResolution Z) : J.cocomplex ⟶ I.cocomplex
cochain_complex.mk_hom _ _ (desc_f_zero f _ _) (desc_f_one f _ _) (desc_f_one_zero_comm f I J).symm (λ n ⟨g, g', w⟩, ⟨(desc_f_succ I J n g g' w.symm).1, (desc_f_succ I J n g g' w.symm).2.symm⟩)
def
category_theory.InjectiveResolution.desc
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "cochain_complex.mk_hom" ]
A morphism in `C` descends to a chain map between injective resolutions.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
desc_commutes {Y Z : C} (f : Z ⟶ Y) (I : InjectiveResolution Y) (J : InjectiveResolution Z) : J.ι ≫ desc f I J = (cochain_complex.single₀ C).map f ≫ I.ι
begin ext n, rcases n with (_|_|n); { dsimp [desc, desc_f_one, desc_f_zero], simp, }, end
lemma
category_theory.InjectiveResolution.desc_commutes
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "cochain_complex.single₀" ]
The resolution maps intertwine the descent of a morphism and that morphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
desc_homotopy_zero_zero {Y Z : C} {I : InjectiveResolution Y} {J : InjectiveResolution Z} (f : I.cocomplex ⟶ J.cocomplex) (comm : I.ι ≫ f = 0) : I.cocomplex.X 1 ⟶ J.cocomplex.X 0
exact.desc (f.f 0) (I.ι.f 0) (I.cocomplex.d 0 1) (abelian.exact.op _ _ I.exact₀) (congr_fun (congr_arg homological_complex.hom.f comm) 0)
def
category_theory.InjectiveResolution.desc_homotopy_zero_zero
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "comm" ]
An auxiliary definition for `desc_homotopy_zero`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
desc_homotopy_zero_one {Y Z : C} {I : InjectiveResolution Y} {J : InjectiveResolution Z} (f : I.cocomplex ⟶ J.cocomplex) (comm : I.ι ≫ f = (0 : _ ⟶ J.cocomplex)) : I.cocomplex.X 2 ⟶ J.cocomplex.X 1
exact.desc (f.f 1 - desc_homotopy_zero_zero f comm ≫ J.cocomplex.d 0 1) (I.cocomplex.d 0 1) (I.cocomplex.d 1 2) (abelian.exact.op _ _ (I.exact _)) (by simp [desc_homotopy_zero_zero, ←category.assoc])
def
category_theory.InjectiveResolution.desc_homotopy_zero_one
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "comm" ]
An auxiliary definition for `desc_homotopy_zero`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
desc_homotopy_zero_succ {Y Z : C} {I : InjectiveResolution Y} {J : InjectiveResolution Z} (f : I.cocomplex ⟶ J.cocomplex) (n : ℕ) (g : I.cocomplex.X (n + 1) ⟶ J.cocomplex.X n) (g' : I.cocomplex.X (n + 2) ⟶ J.cocomplex.X (n + 1)) (w : f.f (n + 1) = I.cocomplex.d (n+1) (n+2) ≫ g' + g ≫ J.cocomplex.d n (n+1)) : ...
exact.desc (f.f (n+2) - g' ≫ J.cocomplex.d _ _) (I.cocomplex.d (n+1) (n+2)) (I.cocomplex.d (n+2) (n+3)) (abelian.exact.op _ _ (I.exact _)) (by simp [preadditive.comp_sub, ←category.assoc, preadditive.sub_comp, show I.cocomplex.d (n+1) (n+2) ≫ g' = f.f (n + 1) - g ≫ J.cocomplex.d n (n+1), by {rw w, s...
def
category_theory.InjectiveResolution.desc_homotopy_zero_succ
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[]
An auxiliary definition for `desc_homotopy_zero`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
desc_homotopy_zero {Y Z : C} {I : InjectiveResolution Y} {J : InjectiveResolution Z} (f : I.cocomplex ⟶ J.cocomplex) (comm : I.ι ≫ f = 0) : homotopy f 0
homotopy.mk_coinductive _ (desc_homotopy_zero_zero f comm) (by simp [desc_homotopy_zero_zero]) (desc_homotopy_zero_one f comm) (by simp [desc_homotopy_zero_one]) (λ n ⟨g, g', w⟩, ⟨desc_homotopy_zero_succ f n g g' (by simp only [w, add_comm]), by simp [desc_homotopy_zero_succ, w]⟩)
def
category_theory.InjectiveResolution.desc_homotopy_zero
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "comm", "homotopy", "homotopy.mk_coinductive" ]
Any descent of the zero morphism is homotopic to zero.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
desc_homotopy {Y Z : C} (f : Y ⟶ Z) {I : InjectiveResolution Y} {J : InjectiveResolution Z} (g h : I.cocomplex ⟶ J.cocomplex) (g_comm : I.ι ≫ g = (cochain_complex.single₀ C).map f ≫ J.ι) (h_comm : I.ι ≫ h = (cochain_complex.single₀ C).map f ≫ J.ι) : homotopy g h
homotopy.equiv_sub_zero.inv_fun (desc_homotopy_zero _ (by simp [g_comm, h_comm]))
def
category_theory.InjectiveResolution.desc_homotopy
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "cochain_complex.single₀", "homotopy" ]
Two descents of the same morphism are homotopic.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
desc_id_homotopy (X : C) (I : InjectiveResolution X) : homotopy (desc (𝟙 X) I I) (𝟙 I.cocomplex)
by apply desc_homotopy (𝟙 X); simp
def
category_theory.InjectiveResolution.desc_id_homotopy
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "homotopy" ]
The descent of the identity morphism is homotopic to the identity cochain map.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
desc_comp_homotopy {X Y Z : C} (f : X ⟶ Y) (g : Y ⟶ Z) (I : InjectiveResolution X) (J : InjectiveResolution Y) (K : InjectiveResolution Z) : homotopy (desc (f ≫ g) K I) (desc f J I ≫ desc g K J)
by apply desc_homotopy (f ≫ g); simp
def
category_theory.InjectiveResolution.desc_comp_homotopy
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "homotopy" ]
The descent of a composition is homotopic to the composition of the descents.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homotopy_equiv {X : C} (I J : InjectiveResolution X) : homotopy_equiv I.cocomplex J.cocomplex
{ hom := desc (𝟙 X) J I, inv := desc (𝟙 X) I J, homotopy_hom_inv_id := (desc_comp_homotopy (𝟙 X) (𝟙 X) I J I).symm.trans $ by simpa [category.id_comp] using desc_id_homotopy _ _, homotopy_inv_hom_id := (desc_comp_homotopy (𝟙 X) (𝟙 X) J I J).symm.trans $ by simpa [category.id_comp] using desc_id_homo...
def
category_theory.InjectiveResolution.homotopy_equiv
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "homotopy_equiv" ]
Any two injective resolutions are homotopy equivalent.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homotopy_equiv_hom_ι {X : C} (I J : InjectiveResolution X) : I.ι ≫ (homotopy_equiv I J).hom = J.ι
by simp [homotopy_equiv]
lemma
category_theory.InjectiveResolution.homotopy_equiv_hom_ι
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "homotopy_equiv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homotopy_equiv_inv_ι {X : C} (I J : InjectiveResolution X) : J.ι ≫ (homotopy_equiv I J).inv = I.ι
by simp [homotopy_equiv]
lemma
category_theory.InjectiveResolution.homotopy_equiv_inv_ι
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "homotopy_equiv" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
injective_resolution (Z : C) [has_injective_resolution Z] : cochain_complex C ℕ
(has_injective_resolution.out Z).some.cocomplex
abbreviation
category_theory.injective_resolution
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "cochain_complex" ]
An arbitrarily chosen injective resolution of an object.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
injective_resolution.ι (Z : C) [has_injective_resolution Z] : (cochain_complex.single₀ C).obj Z ⟶ injective_resolution Z
(has_injective_resolution.out Z).some.ι
abbreviation
category_theory.injective_resolution.ι
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "cochain_complex.single₀" ]
The cochain map from cochain complex consisting of `Z` supported in degree `0` back to the arbitrarily chosen injective resolution `injective_resolution Z`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
injective_resolution.desc {X Y : C} (f : X ⟶ Y) [has_injective_resolution X] [has_injective_resolution Y] : injective_resolution X ⟶ injective_resolution Y
InjectiveResolution.desc f _ _
abbreviation
category_theory.injective_resolution.desc
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[]
The descent of a morphism to a cochain map between the arbitrarily chosen injective resolutions.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
injective_resolutions : C ⥤ homotopy_category C (complex_shape.up ℕ)
{ obj := λ X, (homotopy_category.quotient _ _).obj (injective_resolution X), map := λ X Y f, (homotopy_category.quotient _ _).map (injective_resolution.desc f), map_id' := λ X, begin rw ←(homotopy_category.quotient _ _).map_id, apply homotopy_category.eq_of_homotopy, apply InjectiveResolution.desc_id_ho...
def
category_theory.injective_resolutions
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "complex_shape.up", "homotopy_category", "homotopy_category.eq_of_homotopy", "homotopy_category.quotient", "map_comp", "map_id" ]
Taking injective resolutions is functorial, if considered with target the homotopy category (`ℕ`-indexed cochain complexes and chain maps up to homotopy).
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exact_f_d {X Y : C} (f : X ⟶ Y) : exact f (d f)
(abelian.exact_iff _ _).2 $ ⟨by simp, zero_of_comp_mono (ι _) $ by rw [category.assoc, kernel.condition]⟩
lemma
category_theory.exact_f_d
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_cocomplex (Z : C) : cochain_complex C ℕ
cochain_complex.mk' (injective.under Z) (injective.syzygies (injective.ι Z)) (injective.d (injective.ι Z)) (λ ⟨X, Y, f⟩, ⟨injective.syzygies f, injective.d f, (exact_f_d f).w⟩)
def
category_theory.InjectiveResolution.of_cocomplex
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "cochain_complex", "cochain_complex.mk'" ]
Auxiliary definition for `InjectiveResolution.of`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of (Z : C) : InjectiveResolution Z
{ cocomplex := of_cocomplex Z, ι := cochain_complex.mk_hom _ _ (injective.ι Z) 0 (by { simp only [of_cocomplex_d, eq_self_iff_true, eq_to_hom_refl, category.comp_id, dite_eq_ite, if_true, comp_zero], exact (exact_f_d (injective.ι Z)).w, } ) (λ n _, ⟨0, by ext⟩), injective := by { rintros (_|_|_|n); ...
def
category_theory.InjectiveResolution.of
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "cochain_complex.mk_hom", "dite_eq_ite" ]
In any abelian category with enough injectives, `InjectiveResolution.of Z` constructs an injective resolution of the object `Z`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homological_complex.hom.from_single₀_InjectiveResolution (X : cochain_complex C ℕ) (Y : C) (f : (cochain_complex.single₀ C).obj Y ⟶ X) [quasi_iso f] (H : ∀ n, injective (X.X n)) : InjectiveResolution Y
{ cocomplex := X, ι := f, injective := H, exact₀ := f.from_single₀_exact_f_d_at_zero, exact := f.from_single₀_exact_at_succ, mono := f.from_single₀_mono_at_zero }
def
homological_complex.hom.homological_complex.hom.from_single₀_InjectiveResolution
category_theory.abelian
src/category_theory/abelian/injective_resolution.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.injective_resolution", "algebra.homology.homotopy_category" ]
[ "cochain_complex", "cochain_complex.single₀", "quasi_iso" ]
If `X` is a cochain complex of injective objects and we have a quasi-isomorphism `f : Y[0] ⟶ X`, then `X` is an injective resolution of `Y.`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_exact_of_preserves_finite_colimits_of_epi [preserves_finite_colimits F] [epi g] (ex : exact f g) : exact (F.map f) (F.map g)
abelian.exact_of_is_cokernel _ _ (by simp [← functor.map_comp, ex.w]) $ limits.is_colimit_cofork_map_of_is_colimit' _ ex.w (abelian.is_colimit_of_exact_of_epi _ _ ex)
lemma
category_theory.abelian.functor.preserves_exact_of_preserves_finite_colimits_of_epi
category_theory.abelian
src/category_theory/abelian/left_derived.lean
[ "category_theory.abelian.homology", "category_theory.functor.left_derived", "category_theory.abelian.projective", "category_theory.limits.constructions.epi_mono" ]
[]
If `preserves_finite_colimits F` and `epi g`, then `exact (F.map f) (F.map g)` if `exact f g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exact_of_map_projective_resolution (P: ProjectiveResolution X) [preserves_finite_colimits F] : exact (((F.map_homological_complex (complex_shape.down ℕ)).obj P.complex).d_to 0) (F.map (P.π.f 0))
preadditive.exact_of_iso_of_exact' (F.map (P.complex.d 1 0)) (F.map (P.π.f 0)) _ _ (homological_complex.X_prev_iso ((F.map_homological_complex _).obj P.complex) rfl).symm (iso.refl _) (iso.refl _) (by simp) (by simp) (preserves_exact_of_preserves_finite_colimits_of_epi _ (P.exact₀))
lemma
category_theory.abelian.functor.exact_of_map_projective_resolution
category_theory.abelian
src/category_theory/abelian/left_derived.lean
[ "category_theory.abelian.homology", "category_theory.functor.left_derived", "category_theory.abelian.projective", "category_theory.limits.constructions.epi_mono" ]
[ "complex_shape.down", "homological_complex.X_prev_iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_derived_zero_to_self_app [enough_projectives C] {X : C} (P : ProjectiveResolution X) : (F.left_derived 0).obj X ⟶ F.obj X
(left_derived_obj_iso F 0 P).hom ≫ homology.desc' _ _ _ (kernel.ι _ ≫ (F.map (P.π.f 0))) begin rw [kernel.lift_ι_assoc, homological_complex.d_to_eq _ (by simp : (complex_shape.down ℕ).rel 1 0), map_homological_complex_obj_d, category.assoc, ← functor.map_comp], simp end
def
category_theory.abelian.functor.left_derived_zero_to_self_app
category_theory.abelian
src/category_theory/abelian/left_derived.lean
[ "category_theory.abelian.homology", "category_theory.functor.left_derived", "category_theory.abelian.projective", "category_theory.limits.constructions.epi_mono" ]
[ "complex_shape.down", "homological_complex.d_to_eq", "homology.desc'", "rel" ]
Given `P : ProjectiveResolution X`, a morphism `(F.left_derived 0).obj X ⟶ F.obj X`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_derived_zero_to_self_app_inv [enough_projectives C] [preserves_finite_colimits F] {X : C} (P : ProjectiveResolution X) : F.obj X ⟶ (F.left_derived 0).obj X
begin refine ((as_iso (cokernel.desc _ _ (exact_of_map_projective_resolution F P).w)).inv) ≫ _ ≫ (homology_iso_cokernel_lift _ _ _).inv ≫ (left_derived_obj_iso F 0 P).inv, exact cokernel.map _ _ (𝟙 _) (kernel.lift _ (𝟙 _) (by simp)) (by { ext, simp }), end
def
category_theory.abelian.functor.left_derived_zero_to_self_app_inv
category_theory.abelian
src/category_theory/abelian/left_derived.lean
[ "category_theory.abelian.homology", "category_theory.functor.left_derived", "category_theory.abelian.projective", "category_theory.limits.constructions.epi_mono" ]
[ "homology_iso_cokernel_lift" ]
Given `P : ProjectiveResolution X`, a morphism `F.obj X ⟶ (F.left_derived 0).obj X` given `preserves_finite_colimits F`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_derived_zero_to_self_app_comp_inv [enough_projectives C] [preserves_finite_colimits F] {X : C} (P : ProjectiveResolution X) : left_derived_zero_to_self_app F P ≫ left_derived_zero_to_self_app_inv F P = 𝟙 _
begin dsimp [left_derived_zero_to_self_app, left_derived_zero_to_self_app_inv], rw [← category.assoc, ← category.assoc, ← category.assoc, iso.comp_inv_eq, category.id_comp, category.assoc, category.assoc, category.assoc], convert category.comp_id _, rw [← category.assoc, ← category.assoc, iso.comp_inv_eq, c...
lemma
category_theory.abelian.functor.left_derived_zero_to_self_app_comp_inv
category_theory.abelian
src/category_theory/abelian/left_derived.lean
[ "category_theory.abelian.homology", "category_theory.functor.left_derived", "category_theory.abelian.projective", "category_theory.limits.constructions.epi_mono" ]
[ "homology.π'", "homology.π'_desc'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_derived_zero_to_self_app_inv_comp [enough_projectives C] [preserves_finite_colimits F] {X : C} (P : ProjectiveResolution X) : left_derived_zero_to_self_app_inv F P ≫ left_derived_zero_to_self_app F P = 𝟙 _
begin dsimp [left_derived_zero_to_self_app, left_derived_zero_to_self_app_inv], rw [category.assoc, category.assoc, category.assoc, ← category.assoc (F.left_derived_obj_iso 0 P).inv, iso.inv_hom_id, category.id_comp, is_iso.inv_comp_eq, category.comp_id], ext, simp only [cokernel.π_desc_assoc, category....
lemma
category_theory.abelian.functor.left_derived_zero_to_self_app_inv_comp
category_theory.abelian
src/category_theory/abelian/left_derived.lean
[ "category_theory.abelian.homology", "category_theory.functor.left_derived", "category_theory.abelian.projective", "category_theory.limits.constructions.epi_mono" ]
[ "homology.desc'", "homology_iso_cokernel_lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_derived_zero_to_self_app_iso [enough_projectives C] [preserves_finite_colimits F] {X : C} (P : ProjectiveResolution X) : (F.left_derived 0).obj X ≅ F.obj X
{ hom := left_derived_zero_to_self_app _ P, inv := left_derived_zero_to_self_app_inv _ P, hom_inv_id' := left_derived_zero_to_self_app_comp_inv _ P, inv_hom_id' := left_derived_zero_to_self_app_inv_comp _ P }
def
category_theory.abelian.functor.left_derived_zero_to_self_app_iso
category_theory.abelian
src/category_theory/abelian/left_derived.lean
[ "category_theory.abelian.homology", "category_theory.functor.left_derived", "category_theory.abelian.projective", "category_theory.limits.constructions.epi_mono" ]
[]
Given `P : ProjectiveResolution X`, the isomorphism `(F.left_derived 0).obj X ≅ F.obj X` if `preserves_finite_colimits F`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_derived_zero_to_self_natural [enough_projectives C] {X : C} {Y : C} (f : X ⟶ Y) (P : ProjectiveResolution X) (Q : ProjectiveResolution Y) : (F.left_derived 0).map f ≫ left_derived_zero_to_self_app F Q = left_derived_zero_to_self_app F P ≫ F.map f
begin dsimp only [left_derived_zero_to_self_app], rw [functor.left_derived_map_eq F 0 f (ProjectiveResolution.lift f P Q) (by simp), category.assoc, category.assoc, ← category.assoc _ (F.left_derived_obj_iso 0 Q).hom, iso.inv_hom_id, category.id_comp, category.assoc, whisker_eq], dsimp only [homology_func...
lemma
category_theory.abelian.functor.left_derived_zero_to_self_natural
category_theory.abelian
src/category_theory/abelian/left_derived.lean
[ "category_theory.abelian.homology", "category_theory.functor.left_derived", "category_theory.abelian.projective", "category_theory.limits.constructions.epi_mono" ]
[ "homological_complex.congr_hom", "homological_complex.hom.sq_to_right", "homology.π'_desc'", "map_comp" ]
Given `P : ProjectiveResolution X` and `Q : ProjectiveResolution Y` and a morphism `f : X ⟶ Y`, naturality of the square given by `left_derived_zero_to_self_obj_hom.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_derived_zero_iso_self [enough_projectives C] [preserves_finite_colimits F] : (F.left_derived 0) ≅ F
nat_iso.of_components (λ X, left_derived_zero_to_self_app_iso _ (ProjectiveResolution.of X)) (λ X Y f, left_derived_zero_to_self_natural _ _ _ _)
def
category_theory.abelian.functor.left_derived_zero_iso_self
category_theory.abelian
src/category_theory/abelian/left_derived.lean
[ "category_theory.abelian.homology", "category_theory.functor.left_derived", "category_theory.abelian.projective", "category_theory.limits.constructions.epi_mono" ]
[]
Given `preserves_finite_colimits F`, the natural isomorphism `(F.left_derived 0) ≅ F`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
non_preadditive_abelian extends has_zero_morphisms C, normal_mono_category C, normal_epi_category C
[has_zero_object : has_zero_object C] [has_kernels : has_kernels C] [has_cokernels : has_cokernels C] [has_finite_products : has_finite_products C] [has_finite_coproducts : has_finite_coproducts C]
class
category_theory.non_preadditive_abelian
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
We call a category `non_preadditive_abelian` if it has a zero object, kernels, cokernels, binary products and coproducts, and every monomorphism and every epimorphism is normal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_iso_factor_thru_image [mono f] : is_iso (abelian.factor_thru_image f)
is_iso_of_mono_of_epi _
instance
category_theory.non_preadditive_abelian.is_iso_factor_thru_image
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_iso_factor_thru_coimage [epi f] : is_iso (abelian.factor_thru_coimage f)
is_iso_of_mono_of_epi _
instance
category_theory.non_preadditive_abelian.is_iso_factor_thru_coimage
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
epi_is_cokernel_of_kernel [epi f] (s : fork f 0) (h : is_limit s) : is_colimit (cokernel_cofork.of_π f (kernel_fork.condition s))
is_cokernel.cokernel_iso _ _ (cokernel.of_iso_comp _ _ (limits.is_limit.cone_point_unique_up_to_iso (limit.is_limit _) h) (cone_morphism.w (limits.is_limit.unique_up_to_iso (limit.is_limit _) h).hom _)) (as_iso $ abelian.factor_thru_coimage f) (abelian.coimage.fac f)
def
category_theory.non_preadditive_abelian.epi_is_cokernel_of_kernel
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
In a `non_preadditive_abelian` category, an epi is the cokernel of its kernel. More precisely: If `f` is an epimorphism and `s` is some limit kernel cone on `f`, then `f` is a cokernel of `fork.ι s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mono_is_kernel_of_cokernel [mono f] (s : cofork f 0) (h : is_colimit s) : is_limit (kernel_fork.of_ι f (cokernel_cofork.condition s))
is_kernel.iso_kernel _ _ (kernel.of_comp_iso _ _ (limits.is_colimit.cocone_point_unique_up_to_iso h (colimit.is_colimit _)) (cocone_morphism.w (limits.is_colimit.unique_up_to_iso h $ colimit.is_colimit _).hom _)) (as_iso $ abelian.factor_thru_image f) (abelian.image.fac f)
def
category_theory.non_preadditive_abelian.mono_is_kernel_of_cokernel
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
In a `non_preadditive_abelian` category, a mono is the kernel of its cokernel. More precisely: If `f` is a monomorphism and `s` is some colimit cokernel cocone on `f`, then `f` is a kernel of `cofork.π s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
r (A : C) : A ⟶ cokernel (diag A)
prod.lift (𝟙 A) 0 ≫ cokernel.π (diag A)
abbreviation
category_theory.non_preadditive_abelian.r
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
The composite `A ⟶ A ⨯ A ⟶ cokernel (Δ A)`, where the first map is `(𝟙 A, 0)` and the second map is the canonical projection into the cokernel.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mono_Δ {A : C} : mono (diag A)
mono_of_mono_fac $ prod.lift_fst _ _
instance
category_theory.non_preadditive_abelian.mono_Δ
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mono_r {A : C} : mono (r A)
begin let hl : is_limit (kernel_fork.of_ι (diag A) (cokernel.condition (diag A))), { exact mono_is_kernel_of_cokernel _ (colimit.is_colimit _) }, apply normal_epi_category.mono_of_cancel_zero, intros Z x hx, have hxx : (x ≫ prod.lift (𝟙 A) (0 : A ⟶ A)) ≫ cokernel.π (diag A) = 0, { rw [category.assoc, hx] }...
instance
category_theory.non_preadditive_abelian.mono_r
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
epi_r {A : C} : epi (r A)
begin have hlp : prod.lift (𝟙 A) (0 : A ⟶ A) ≫ limits.prod.snd = 0 := prod.lift_snd _ _, let hp1 : is_limit (kernel_fork.of_ι (prod.lift (𝟙 A) (0 : A ⟶ A)) hlp), { refine fork.is_limit.mk _ (λ s, fork.ι s ≫ limits.prod.fst) _ _, { intro s, ext; simp, erw category.comp_id }, { intros s m h, h...
instance
category_theory.non_preadditive_abelian.epi_r
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_iso_r {A : C} : is_iso (r A)
is_iso_of_mono_of_epi _
instance
category_theory.non_preadditive_abelian.is_iso_r
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
σ {A : C} : A ⨯ A ⟶ A
cokernel.π (diag A) ≫ inv (r A)
abbreviation
category_theory.non_preadditive_abelian.σ
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
The composite `A ⨯ A ⟶ cokernel (diag A) ⟶ A` given by the natural projection into the cokernel followed by the inverse of `r`. In the category of modules, using the normal kernels and cokernels, this map is equal to the map `(a, b) ↦ a - b`, hence the name `σ` for "subtraction".
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diag_σ {X : C} : diag X ≫ σ = 0
by rw [cokernel.condition_assoc, zero_comp]
lemma
category_theory.non_preadditive_abelian.diag_σ
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_σ {X : C} : prod.lift (𝟙 X) 0 ≫ σ = 𝟙 X
by rw [←category.assoc, is_iso.hom_inv_id]
lemma
category_theory.non_preadditive_abelian.lift_σ
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_map {X Y : C} (f : X ⟶ Y) : prod.lift (𝟙 X) 0 ≫ limits.prod.map f f = f ≫ prod.lift (𝟙 Y) 0
by simp
lemma
category_theory.non_preadditive_abelian.lift_map
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_colimit_σ {X : C} : is_colimit (cokernel_cofork.of_π σ diag_σ)
cokernel.cokernel_iso _ σ (as_iso (r X)).symm (by rw [iso.symm_hom, as_iso_inv])
def
category_theory.non_preadditive_abelian.is_colimit_σ
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
σ is a cokernel of Δ X.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
σ_comp {X Y : C} (f : X ⟶ Y) : σ ≫ f = limits.prod.map f f ≫ σ
begin obtain ⟨g, hg⟩ := cokernel_cofork.is_colimit.desc' is_colimit_σ (limits.prod.map f f ≫ σ) (by simp), suffices hfg : f = g, { rw [←hg, cofork.π_of_π, hfg] }, calc f = f ≫ prod.lift (𝟙 Y) 0 ≫ σ : by rw [lift_σ, category.comp_id] ... = prod.lift (𝟙 X) 0 ≫ limits.prod.map f f ≫ σ : by rw lift_map_as...
lemma
category_theory.non_preadditive_abelian.σ_comp
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
This is the key identity satisfied by `σ`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_sub {X Y : C} : has_sub (X ⟶ Y)
⟨λ f g, prod.lift f g ≫ σ⟩
def
category_theory.non_preadditive_abelian.has_sub
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
Subtraction of morphisms in a `non_preadditive_abelian` category.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_neg {X Y : C} : has_neg (X ⟶ Y)
⟨λ f, 0 - f⟩
def
category_theory.non_preadditive_abelian.has_neg
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
Negation of morphisms in a `non_preadditive_abelian` category.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_add {X Y : C} : has_add (X ⟶ Y)
⟨λ f g, f - (-g)⟩
def
category_theory.non_preadditive_abelian.has_add
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
Addition of morphisms in a `non_preadditive_abelian` category.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_def {X Y : C} (a b : X ⟶ Y) : a - b = prod.lift a b ≫ σ
rfl
lemma
category_theory.non_preadditive_abelian.sub_def
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_def {X Y : C} (a b : X ⟶ Y) : a + b = a - (-b)
rfl
lemma
category_theory.non_preadditive_abelian.add_def
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg_def {X Y : C} (a : X ⟶ Y) : -a = 0 - a
rfl
lemma
category_theory.non_preadditive_abelian.neg_def
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_zero {X Y : C} (a : X ⟶ Y) : a - 0 = a
begin rw sub_def, conv_lhs { congr, congr, rw ←category.comp_id a, skip, rw (show 0 = a ≫ (0 : Y ⟶ Y), by simp)}, rw [← prod.comp_lift, category.assoc, lift_σ, category.comp_id] end
lemma
category_theory.non_preadditive_abelian.sub_zero
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_self {X Y : C} (a : X ⟶ Y) : a - a = 0
by rw [sub_def, ←category.comp_id a, ← prod.comp_lift, category.assoc, diag_σ, comp_zero]
lemma
category_theory.non_preadditive_abelian.sub_self
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_sub_lift {X Y : C} (a b c d : X ⟶ Y) : prod.lift a b - prod.lift c d = prod.lift (a - c) (b - d)
begin simp only [sub_def], ext, { rw [category.assoc, σ_comp, prod.lift_map_assoc, prod.lift_fst, prod.lift_fst, prod.lift_fst] }, { rw [category.assoc, σ_comp, prod.lift_map_assoc, prod.lift_snd, prod.lift_snd, prod.lift_snd] } end
lemma
category_theory.non_preadditive_abelian.lift_sub_lift
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_sub_sub {X Y : C} (a b c d : X ⟶ Y) : (a - c) - (b - d) = (a - b) - (c - d)
begin rw [sub_def, ←lift_sub_lift, sub_def, category.assoc, σ_comp, prod.lift_map_assoc], refl end
lemma
category_theory.non_preadditive_abelian.sub_sub_sub
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg_sub {X Y : C} (a b : X ⟶ Y) : (-a) - b = (-b) - a
by conv_lhs { rw [neg_def, ←sub_zero b, sub_sub_sub, sub_zero, ←neg_def] }
lemma
category_theory.non_preadditive_abelian.neg_sub
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg_neg {X Y : C} (a : X ⟶ Y) : -(-a) = a
begin rw [neg_def, neg_def], conv_lhs { congr, rw ←sub_self a }, rw [sub_sub_sub, sub_zero, sub_self, sub_zero] end
lemma
category_theory.non_preadditive_abelian.neg_neg
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_comm {X Y : C} (a b : X ⟶ Y) : a + b = b + a
begin rw [add_def], conv_lhs { rw ←neg_neg a }, rw [neg_def, neg_def, neg_def, sub_sub_sub], conv_lhs {congr, skip, rw [←neg_def, neg_sub] }, rw [sub_sub_sub, add_def, ←neg_def, neg_neg b, neg_def] end
lemma
category_theory.non_preadditive_abelian.add_comm
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_neg {X Y : C} (a b : X ⟶ Y) : a + (-b) = a - b
by rw [add_def, neg_neg]
lemma
category_theory.non_preadditive_abelian.add_neg
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_neg_self {X Y : C} (a : X ⟶ Y) : a + (-a) = 0
by rw [add_neg, sub_self]
lemma
category_theory.non_preadditive_abelian.add_neg_self
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg_add_self {X Y : C} (a : X ⟶ Y) : (-a) + a = 0
by rw [add_comm, add_neg_self]
lemma
category_theory.non_preadditive_abelian.neg_add_self
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg_sub' {X Y : C} (a b : X ⟶ Y) : -(a - b) = (-a) + b
begin rw [neg_def, neg_def], conv_lhs { rw ←sub_self (0 : X ⟶ Y) }, rw [sub_sub_sub, add_def, neg_def] end
lemma
category_theory.non_preadditive_abelian.neg_sub'
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
neg_add {X Y : C} (a b : X ⟶ Y) : -(a + b) = (-a) - b
by rw [add_def, neg_sub', add_neg]
lemma
category_theory.non_preadditive_abelian.neg_add
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_add {X Y : C} (a b c : X ⟶ Y) : (a - b) + c = a - (b - c)
by rw [add_def, neg_def, sub_sub_sub, sub_zero]
lemma
category_theory.non_preadditive_abelian.sub_add
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_assoc {X Y : C} (a b c : X ⟶ Y) : (a + b) + c = a + (b + c)
begin conv_lhs { congr, rw add_def }, rw [sub_add, ←add_neg, neg_sub', neg_neg] end
lemma
category_theory.non_preadditive_abelian.add_assoc
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_zero {X Y : C} (a : X ⟶ Y) : a + 0 = a
by rw [add_def, neg_def, sub_self, sub_zero]
lemma
category_theory.non_preadditive_abelian.add_zero
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_sub {X Y Z : C} (f : X ⟶ Y) (g h : Y ⟶ Z) : f ≫ (g - h) = f ≫ g - f ≫ h
by rw [sub_def, ←category.assoc, prod.comp_lift, sub_def]
lemma
category_theory.non_preadditive_abelian.comp_sub
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sub_comp {X Y Z : C} (f g : X ⟶ Y) (h : Y ⟶ Z) : (f - g) ≫ h = f ≫ h - g ≫ h
by rw [sub_def, category.assoc, σ_comp, ←category.assoc, prod.lift_map, sub_def]
lemma
category_theory.non_preadditive_abelian.sub_comp
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_add (X Y Z : C) (f : X ⟶ Y) (g h : Y ⟶ Z) : f ≫ (g + h) = f ≫ g + f ≫ h
by rw [add_def, comp_sub, neg_def, comp_sub, comp_zero, add_def, neg_def]
lemma
category_theory.non_preadditive_abelian.comp_add
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
add_comp (X Y Z : C) (f g : X ⟶ Y) (h : Y ⟶ Z) : (f + g) ≫ h = f ≫ h + g ≫ h
by rw [add_def, sub_comp, neg_def, sub_comp, zero_comp, add_def, neg_def]
lemma
category_theory.non_preadditive_abelian.add_comp
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preadditive : preadditive C
{ hom_group := λ X Y, { add := (+), add_assoc := add_assoc, zero := 0, zero_add := neg_neg, add_zero := add_zero, neg := λ f, -f, add_left_neg := neg_add_self, add_comm := add_comm }, add_comp' := add_comp, comp_add' := comp_add }
def
category_theory.non_preadditive_abelian.preadditive
category_theory.abelian
src/category_theory/abelian/non_preadditive.lean
[ "category_theory.limits.shapes.finite_products", "category_theory.limits.shapes.kernels", "category_theory.limits.shapes.normal_mono.equalizers", "category_theory.abelian.images", "category_theory.preadditive.basic" ]
[]
Every `non_preadditive_abelian` category is preadditive.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
kernel_op_unop : (kernel f.op).unop ≅ cokernel f
{ hom := (kernel.lift f.op (cokernel.π f).op $ by simp [← op_comp]).unop, inv := cokernel.desc f (kernel.ι f.op).unop $ by { rw [← f.unop_op, ← unop_comp, f.unop_op], simp }, hom_inv_id' := begin rw [← unop_id, ← (cokernel.desc f _ _).unop_op, ← unop_comp], congr' 1, dsimp, ext, simp [← op_c...
def
category_theory.kernel_op_unop
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[]
The kernel of `f.op` is the opposite of `cokernel f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cokernel_op_unop : (cokernel f.op).unop ≅ kernel f
{ hom := kernel.lift f (cokernel.π f.op).unop $ by { rw [← f.unop_op, ← unop_comp, f.unop_op], simp }, inv := (cokernel.desc f.op (kernel.ι f).op $ by simp [← op_comp]).unop, hom_inv_id' := begin rw [← unop_id, ← (kernel.lift f _ _).unop_op, ← unop_comp], congr' 1, dsimp, ext, simp [← op_com...
def
category_theory.cokernel_op_unop
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[]
The cokernel of `f.op` is the opposite of `kernel f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
kernel_unop_op : opposite.op (kernel g.unop) ≅ cokernel g
(cokernel_op_unop g.unop).op
def
category_theory.kernel_unop_op
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[ "opposite.op" ]
The kernel of `g.unop` is the opposite of `cokernel g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cokernel_unop_op : opposite.op (cokernel g.unop) ≅ kernel g
(kernel_op_unop g.unop).op
def
category_theory.cokernel_unop_op
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[ "opposite.op" ]
The cokernel of `g.unop` is the opposite of `kernel g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cokernel.π_op : (cokernel.π f.op).unop = (cokernel_op_unop f).hom ≫ kernel.ι f ≫ eq_to_hom (opposite.unop_op _).symm
by simp [cokernel_op_unop]
lemma
category_theory.cokernel.π_op
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[ "opposite.unop_op" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
kernel.ι_op : (kernel.ι f.op).unop = eq_to_hom (opposite.unop_op _) ≫ cokernel.π f ≫ (kernel_op_unop f).inv
by simp [kernel_op_unop]
lemma
category_theory.kernel.ι_op
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[ "opposite.unop_op" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
kernel_op_op : kernel f.op ≅ opposite.op (cokernel f)
(kernel_op_unop f).op.symm
def
category_theory.kernel_op_op
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[ "opposite.op" ]
The kernel of `f.op` is the opposite of `cokernel f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cokernel_op_op : cokernel f.op ≅ opposite.op (kernel f)
(cokernel_op_unop f).op.symm
def
category_theory.cokernel_op_op
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[ "opposite.op" ]
The cokernel of `f.op` is the opposite of `kernel f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
kernel_unop_unop : kernel g.unop ≅ (cokernel g).unop
(kernel_unop_op g).unop.symm
def
category_theory.kernel_unop_unop
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[]
The kernel of `g.unop` is the opposite of `cokernel g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
kernel.ι_unop : (kernel.ι g.unop).op = eq_to_hom (opposite.op_unop _) ≫ cokernel.π g ≫ (kernel_unop_op g).inv
by simp
lemma
category_theory.kernel.ι_unop
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[ "opposite.op_unop" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cokernel.π_unop : (cokernel.π g.unop).op = (cokernel_unop_op g).hom ≫ kernel.ι g ≫ eq_to_hom (opposite.op_unop _).symm
by simp
lemma
category_theory.cokernel.π_unop
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[ "opposite.op_unop" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cokernel_unop_unop : cokernel g.unop ≅ (kernel g).unop
(cokernel_unop_op g).unop.symm
def
category_theory.cokernel_unop_unop
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[]
The cokernel of `g.unop` is the opposite of `kernel g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image_unop_op : opposite.op (image g.unop) ≅ image g
(abelian.image_iso_image _).op ≪≫ (cokernel_op_op _).symm ≪≫ cokernel_iso_of_eq (cokernel.π_unop _) ≪≫ (cokernel_epi_comp _ _) ≪≫ (cokernel_comp_is_iso _ _) ≪≫ (abelian.coimage_iso_image' _)
def
category_theory.image_unop_op
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[ "opposite.op" ]
The opposite of the image of `g.unop` is the image of `g.`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image_op_op : opposite.op (image f) ≅ image f.op
image_unop_op f.op
def
category_theory.image_op_op
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[ "opposite.op" ]
The opposite of the image of `f` is the image of `f.op`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image_op_unop : (image f.op).unop ≅ image f
(image_unop_op f.op).unop
def
category_theory.image_op_unop
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[]
The image of `f.op` is the opposite of the image of `f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image_unop_unop : (image g).unop ≅ image g.unop
(image_unop_op g).unop
def
category_theory.image_unop_unop
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[]
The image of `g` is the opposite of the image of `g.unop.`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image_ι_op_comp_image_unop_op_hom : (image.ι g.unop).op ≫ (image_unop_op g).hom = factor_thru_image g
begin dunfold image_unop_op, simp only [←category.assoc, ←op_comp, iso.trans_hom, iso.symm_hom, iso.op_hom, cokernel_op_op_inv, cokernel_comp_is_iso_hom, cokernel_epi_comp_hom, cokernel_iso_of_eq_hom_comp_desc_assoc, abelian.coimage_iso_image'_hom, eq_to_hom_refl, is_iso.inv_id, category.id_comp (cokern...
lemma
category_theory.image_ι_op_comp_image_unop_op_hom
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[ "quiver.hom.op_unop" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image_unop_op_hom_comp_image_ι : (image_unop_op g).hom ≫ image.ι g = (factor_thru_image g.unop).op
by simp only [←cancel_epi (image.ι g.unop).op, ←category.assoc, image_ι_op_comp_image_unop_op_hom, ←op_comp, image.fac, quiver.hom.op_unop]
lemma
category_theory.image_unop_op_hom_comp_image_ι
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[ "quiver.hom.op_unop" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
factor_thru_image_comp_image_unop_op_inv : factor_thru_image g ≫ (image_unop_op g).inv = (image.ι g.unop).op
by rw [iso.comp_inv_eq, image_ι_op_comp_image_unop_op_hom]
lemma
category_theory.factor_thru_image_comp_image_unop_op_inv
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image_unop_op_inv_comp_op_factor_thru_image : (image_unop_op g).inv ≫ (factor_thru_image g.unop).op = image.ι g
by rw [iso.inv_comp_eq, image_unop_op_hom_comp_image_ι]
lemma
category_theory.image_unop_op_inv_comp_op_factor_thru_image
category_theory.abelian
src/category_theory/abelian/opposite.lean
[ "category_theory.abelian.basic", "category_theory.preadditive.opposite", "category_theory.limits.opposites" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exact_d_f [enough_projectives C] {X Y : C} (f : X ⟶ Y) : exact (d f) f
(abelian.exact_iff _ _).2 $ ⟨by simp, zero_of_epi_comp (π _) $ by rw [←category.assoc, cokernel.condition]⟩
lemma
category_theory.exact_d_f
category_theory.abelian
src/category_theory/abelian/projective.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.projective_resolution", "category_theory.preadditive.yoneda.limits", "category_theory.preadditive.yoneda.projective" ]
[]
When `C` is abelian, `projective.d f` and `f` are exact.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_finite_colimits_preadditive_coyoneda_obj_of_projective (P : C) [hP : projective P] : preserves_finite_colimits (preadditive_coyoneda_obj (op P))
begin letI := (projective_iff_preserves_epimorphisms_preadditive_coyoneda_obj' P).mp hP, apply functor.preserves_finite_colimits_of_preserves_epis_and_kernels, end
def
category_theory.preserves_finite_colimits_preadditive_coyoneda_obj_of_projective
category_theory.abelian
src/category_theory/abelian/projective.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.projective_resolution", "category_theory.preadditive.yoneda.limits", "category_theory.preadditive.yoneda.projective" ]
[]
The preadditive Co-Yoneda functor on `P` preserves colimits if `P` is projective.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
projective_of_preserves_finite_colimits_preadditive_coyoneda_obj (P : C) [hP : preserves_finite_colimits (preadditive_coyoneda_obj (op P))] : projective P
begin rw projective_iff_preserves_epimorphisms_preadditive_coyoneda_obj', apply_instance end
lemma
category_theory.projective_of_preserves_finite_colimits_preadditive_coyoneda_obj
category_theory.abelian
src/category_theory/abelian/projective.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.projective_resolution", "category_theory.preadditive.yoneda.limits", "category_theory.preadditive.yoneda.projective" ]
[]
An object is projective if its preadditive Co-Yoneda functor preserves finite colimits.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_complex (Z : C) : chain_complex C ℕ
chain_complex.mk' (projective.over Z) (projective.syzygies (projective.π Z)) (projective.d (projective.π Z)) (λ ⟨X, Y, f⟩, ⟨projective.syzygies f, projective.d f, (exact_d_f f).w⟩)
def
category_theory.ProjectiveResolution.of_complex
category_theory.abelian
src/category_theory/abelian/projective.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.projective_resolution", "category_theory.preadditive.yoneda.limits", "category_theory.preadditive.yoneda.projective" ]
[ "chain_complex", "chain_complex.mk'" ]
Auxiliary definition for `ProjectiveResolution.of`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of (Z : C) : ProjectiveResolution Z
{ complex := of_complex Z, π := chain_complex.mk_hom _ _ (projective.π Z) 0 (by { simp, exact (exact_d_f (projective.π Z)).w.symm, }) (λ n _, ⟨0, by ext⟩), projective := by { rintros (_|_|_|n); apply projective.projective_over, }, exact₀ := by simpa using exact_d_f (projective.π Z), exact := by { rintro...
def
category_theory.ProjectiveResolution.of
category_theory.abelian
src/category_theory/abelian/projective.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.projective_resolution", "category_theory.preadditive.yoneda.limits", "category_theory.preadditive.yoneda.projective" ]
[ "chain_complex.mk_hom", "complex" ]
In any abelian category with enough projectives, `ProjectiveResolution.of Z` constructs a projective resolution of the object `Z`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_single₀_ProjectiveResolution {X : chain_complex C ℕ} {Y : C} (f : X ⟶ (chain_complex.single₀ C).obj Y) [quasi_iso f] (H : ∀ n, projective (X.X n)) : ProjectiveResolution Y
{ complex := X, π := f, projective := H, exact₀ := f.to_single₀_exact_d_f_at_zero, exact := f.to_single₀_exact_at_succ, epi := f.to_single₀_epi_at_zero }
def
homological_complex.hom.to_single₀_ProjectiveResolution
category_theory.abelian
src/category_theory/abelian/projective.lean
[ "algebra.homology.quasi_iso", "category_theory.preadditive.projective_resolution", "category_theory.preadditive.yoneda.limits", "category_theory.preadditive.yoneda.projective" ]
[ "chain_complex", "chain_complex.single₀", "complex", "quasi_iso" ]
If `X` is a chain complex of projective objects and we have a quasi-isomorphism `f : X ⟶ Y[0]`, then `X` is a projective resolution of `Y.`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83