statement
stringlengths
1
2.88k
proof
stringlengths
0
13.9k
type
stringclasses
10 values
symbolic_name
stringlengths
1
131
library
stringclasses
417 values
filename
stringlengths
17
80
imports
listlengths
0
16
deps
listlengths
0
64
docstring
stringlengths
0
10.2k
source_url
stringclasses
1 value
commit
stringclasses
1 value
image_to_kernel_epi_of_epi_of_zero [has_images V] [epi f] : epi (image_to_kernel f (0 : B ⟶ C) (by simp))
begin simp only [image_to_kernel_zero_right], haveI := epi_image_of_epi f, rw ←image_subobject_arrow, refine @epi_comp _ _ _ _ _ _ (epi_comp _ _) _ _, end
instance
image_to_kernel_epi_of_epi_of_zero
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "image_to_kernel", "image_to_kernel_zero_right" ]
`image_to_kernel` for `A --f--> B --0--> C`, where `g` is an epi is itself an epi (i.e. the sequence is exact at `B`).
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology {A B C : V} (f : A ⟶ B) [has_image f] (g : B ⟶ C) [has_kernel g] (w : f ≫ g = 0) [has_cokernel (image_to_kernel f g w)] : V
cokernel (image_to_kernel f g w)
def
homology
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "image_to_kernel" ]
The homology of a pair of morphisms `f : A ⟶ B` and `g : B ⟶ C` satisfying `f ≫ g = 0` is the cokernel of the `image_to_kernel` morphism for `f` and `g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology.π : (kernel_subobject g : V) ⟶ homology f g w
cokernel.π _
def
homology.π
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology" ]
The morphism from cycles to homology.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology.condition : image_to_kernel f g w ≫ homology.π f g w = 0
cokernel.condition _
lemma
homology.condition
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology.π", "image_to_kernel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology.desc {D : V} (k : (kernel_subobject g : V) ⟶ D) (p : image_to_kernel f g w ≫ k = 0) : homology f g w ⟶ D
cokernel.desc _ k p
def
homology.desc
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology", "image_to_kernel" ]
To construct a map out of homology, it suffices to construct a map out of the cycles which vanishes on boundaries.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology.π_desc {D : V} (k : (kernel_subobject g : V) ⟶ D) (p : image_to_kernel f g w ≫ k = 0) : homology.π f g w ≫ homology.desc f g w k p = k
by { simp [homology.π, homology.desc], }
lemma
homology.π_desc
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology.desc", "homology.π", "image_to_kernel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology.ext {D : V} {k k' : homology f g w ⟶ D} (p : homology.π f g w ≫ k = homology.π f g w ≫ k') : k = k'
by { ext, exact p, }
lemma
homology.ext
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology", "homology.π" ]
To check two morphisms out of `homology f g w` are equal, it suffices to check on cycles.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology_of_zero_right [has_cokernel (image_to_kernel f (0 : B ⟶ C) comp_zero)] [has_cokernel f] [has_cokernel (image.ι f)] [epi (factor_thru_image f)] : homology f (0 : B ⟶ C) comp_zero ≅ cokernel f
(cokernel.map_iso _ _ (image_subobject_iso _) ((kernel_subobject_iso 0).trans kernel_zero_iso_source) (by simp)).trans (cokernel_image_ι _)
def
homology_of_zero_right
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology", "image_to_kernel" ]
The cokernel of the map `Im f ⟶ Ker 0` is isomorphic to the cokernel of `f.`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology_of_zero_left [has_zero_object V] [has_kernels V] [has_image (0 : A ⟶ B)] [has_cokernel (image_to_kernel (0 : A ⟶ B) g zero_comp)] : homology (0 : A ⟶ B) g zero_comp ≅ kernel g
((cokernel_iso_of_eq $ image_to_kernel_zero_left _).trans cokernel_zero_iso_target).trans (kernel_subobject_iso _)
def
homology_of_zero_left
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology", "image_to_kernel", "image_to_kernel_zero_left" ]
The kernel of the map `Im 0 ⟶ Ker f` is isomorphic to the kernel of `f.`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology_zero_zero [has_zero_object V] [has_image (0 : A ⟶ B)] [has_cokernel (image_to_kernel (0 : A ⟶ B) (0 : B ⟶ C) (by simp))] : homology (0 : A ⟶ B) (0 : B ⟶ C) (by simp) ≅ B
{ hom := homology.desc (0 : A ⟶ B) (0 : B ⟶ C) (by simp) (kernel_subobject 0).arrow (by simp), inv := inv (kernel_subobject 0).arrow ≫ homology.π _ _ _, }
def
homology_zero_zero
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology", "homology.desc", "homology.π", "image_to_kernel" ]
`homology 0 0 _` is just the middle object.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image_subobject_map_comp_image_to_kernel (p : α.right = β.left) : image_to_kernel f g w ≫ kernel_subobject_map β = image_subobject_map α ≫ image_to_kernel f' g' w'
by { ext, simp [p], }
lemma
image_subobject_map_comp_image_to_kernel
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "image_to_kernel" ]
Given compatible commutative squares between a pair `f g` and a pair `f' g'` satisfying `f ≫ g = 0` and `f' ≫ g' = 0`, the `image_to_kernel` morphisms intertwine the induced map on kernels and the induced map on images.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology.map (p : α.right = β.left) : homology f g w ⟶ homology f' g' w'
cokernel.desc _ (kernel_subobject_map β ≫ cokernel.π _) begin rw [image_subobject_map_comp_image_to_kernel_assoc w w' α β p], simp only [cokernel.condition, comp_zero], end
def
homology.map
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology" ]
Given compatible commutative squares between a pair `f g` and a pair `f' g'` satisfying `f ≫ g = 0` and `f' ≫ g' = 0`, we get a morphism on homology.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology.π_map (p : α.right = β.left) : homology.π f g w ≫ homology.map w w' α β p = kernel_subobject_map β ≫ homology.π f' g' w'
by simp only [homology.π, homology.map, cokernel.π_desc]
lemma
homology.π_map
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology.map", "homology.π" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology.map_desc (p : α.right = β.left) {D : V} (k : (kernel_subobject g' : V) ⟶ D) (z : image_to_kernel f' g' w' ≫ k = 0) : homology.map w w' α β p ≫ homology.desc f' g' w' k z = homology.desc f g w (kernel_subobject_map β ≫ k) (by simp only [image_subobject_map_comp_image_to_kernel_assoc w w' α β p, z,...
by ext; simp only [homology.π_desc, homology.π_map_assoc]
lemma
homology.map_desc
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology.desc", "homology.map", "homology.π_desc", "image_to_kernel" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology.map_id : homology.map w w (𝟙 _) (𝟙 _) rfl = 𝟙 _
by ext; simp only [homology.π_map, kernel_subobject_map_id, category.id_comp, category.comp_id]
lemma
homology.map_id
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology.map", "homology.π_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology.comp_right_eq_comp_left {V : Type*} [category V] {A₁ B₁ C₁ A₂ B₂ C₂ A₃ B₃ C₃ : V} {f₁ : A₁ ⟶ B₁} {g₁ : B₁ ⟶ C₁} {f₂ : A₂ ⟶ B₂} {g₂ : B₂ ⟶ C₂} {f₃ : A₃ ⟶ B₃} {g₃ : B₃ ⟶ C₃} {α₁ : arrow.mk f₁ ⟶ arrow.mk f₂} {β₁ : arrow.mk g₁ ⟶ arrow.mk g₂} {α₂ : arrow.mk f₂ ⟶ arrow.mk f₃} {β₂ : arrow.mk g₂ ⟶ arrow.mk g₃}...
by simp only [comma.comp_left, comma.comp_right, p₁, p₂]
lemma
homology.comp_right_eq_comp_left
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[]
Auxiliary lemma for homology computations.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology.map_comp (p₁ : α₁.right = β₁.left) (p₂ : α₂.right = β₂.left) : homology.map w₁ w₂ α₁ β₁ p₁ ≫ homology.map w₂ w₃ α₂ β₂ p₂ = homology.map w₁ w₃ (α₁ ≫ α₂) (β₁ ≫ β₂) (homology.comp_right_eq_comp_left p₁ p₂)
by ext; simp only [kernel_subobject_map_comp, homology.π_map_assoc, homology.π_map, category.assoc]
lemma
homology.map_comp
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology.comp_right_eq_comp_left", "homology.map", "homology.π_map" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology.map_iso (α : arrow.mk f₁ ≅ arrow.mk f₂) (β : arrow.mk g₁ ≅ arrow.mk g₂) (p : α.hom.right = β.hom.left) : homology f₁ g₁ w₁ ≅ homology f₂ g₂ w₂
{ hom := homology.map w₁ w₂ α.hom β.hom p, inv := homology.map w₂ w₁ α.inv β.inv (by { rw [← cancel_mono (α.hom.right), ← comma.comp_right, α.inv_hom_id, comma.id_right, p, ← comma.comp_left, β.inv_hom_id, comma.id_left], refl }), hom_inv_id' := by { rw [homology.map_comp], convert homology.map_id _; rw [is...
def
homology.map_iso
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology", "homology.map", "homology.map_comp", "homology.map_id" ]
An isomorphism between two three-term complexes induces an isomorphism on homology.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
aux_tac : tactic unit
`[ dsimp only [auto_param_eq], erw [category.id_comp, category.comp_id], cases pf, cases pg, refl ]
def
aux_tac
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[]
Custom tactic to golf and speedup boring proofs in `homology.congr`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology.congr (pf : f = f') (pg : g = g') : homology f g w ≅ homology f' g' w'
{ hom := homology.map w w' ⟨𝟙 _, 𝟙 _, by aux_tac⟩ ⟨𝟙 _, 𝟙 _, by aux_tac⟩ rfl, inv := homology.map w' w ⟨𝟙 _, 𝟙 _, by aux_tac⟩ ⟨𝟙 _, 𝟙 _, by aux_tac⟩ rfl, hom_inv_id' := begin cases pf, cases pg, rw [homology.map_comp, ← homology.map_id], congr' 1; exact category.comp_id _, end, inv_hom_id' := be...
def
homology.congr
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology", "homology.map", "homology.map_comp", "homology.map_id" ]
`homology f g w ≅ homology f' g' w'` if `f = f'` and `g = g'`. (Note the objects are not changing here.)
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image_to_kernel' (w : f ≫ g = 0) : image f ⟶ kernel g
kernel.lift g (image.ι f) (by { ext, simpa using w, })
def
image_to_kernel'
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[]
While `image_to_kernel f g w` provides a morphism `image_subobject f ⟶ kernel_subobject g` in terms of the subobject API, this variant provides a morphism `image f ⟶ kernel g`, which is sometimes more convenient.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image_subobject_iso_image_to_kernel' (w : f ≫ g = 0) : (image_subobject_iso f).hom ≫ image_to_kernel' f g w = image_to_kernel f g w ≫ (kernel_subobject_iso g).hom
by { ext, simp [image_to_kernel'], }
lemma
image_subobject_iso_image_to_kernel'
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "image_to_kernel", "image_to_kernel'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image_to_kernel'_kernel_subobject_iso (w : f ≫ g = 0) : image_to_kernel' f g w ≫ (kernel_subobject_iso g).inv = (image_subobject_iso f).inv ≫ image_to_kernel f g w
by { ext, simp [image_to_kernel'], }
lemma
image_to_kernel'_kernel_subobject_iso
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "image_to_kernel", "image_to_kernel'" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology_iso_cokernel_image_to_kernel' (w : f ≫ g = 0) : homology f g w ≅ cokernel (image_to_kernel' f g w)
{ hom := cokernel.map _ _ (image_subobject_iso f).hom (kernel_subobject_iso g).hom (by simp only [image_subobject_iso_image_to_kernel']), inv := cokernel.map _ _ (image_subobject_iso f).inv (kernel_subobject_iso g).inv (by simp only [image_to_kernel'_kernel_subobject_iso]), hom_inv_id' := begin apply co...
def
homology_iso_cokernel_image_to_kernel'
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology", "image_subobject_iso_image_to_kernel'", "image_to_kernel'", "image_to_kernel'_kernel_subobject_iso" ]
`homology f g w` can be computed as the cokernel of `image_to_kernel' f g w`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology_iso_cokernel_lift (w : f ≫ g = 0) : homology f g w ≅ cokernel (kernel.lift g f w)
begin refine homology_iso_cokernel_image_to_kernel' f g w ≪≫ _, have p : factor_thru_image f ≫ image_to_kernel' f g w = kernel.lift g f w, { ext, simp [image_to_kernel'], }, exact (cokernel_epi_comp _ _).symm ≪≫ cokernel_iso_of_eq p, end
def
homology_iso_cokernel_lift
algebra.homology
src/algebra/homology/image_to_kernel.lean
[ "category_theory.subobject.limits" ]
[ "homology", "homology_iso_cokernel_image_to_kernel'", "image_to_kernel'" ]
`homology f g w` can be computed as the cokernel of `kernel.lift g f w`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ring_mod_ideals (I : D ⥤ ideal R) : D ⥤ Module.{u} R
{ obj := λ t, Module.of R $ R ⧸ (I.obj t), map := λ s t w, submodule.mapq _ _ (linear_map.id) (I.map w).down.down }
def
local_cohomology.ring_mod_ideals
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[ "Module.of", "ideal", "linear_map.id", "submodule.mapq" ]
The directed system of `R`-modules of the form `R/J`, where `J` is an ideal of `R`, determined by the functor `I`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
Module_enough_projectives' : enough_projectives (Module.{u} R)
Module.Module_enough_projectives.{u}
instance
local_cohomology.Module_enough_projectives'
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diagram (I : D ⥤ ideal R) (i : ℕ) : Dᵒᵖ ⥤ Module.{u} R ⥤ Module.{u} R
(ring_mod_ideals I).op ⋙ Ext R (Module.{u} R) i
def
local_cohomology.diagram
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[ "Ext", "ideal" ]
The diagram we will take the colimit of to define local cohomology, corresponding to the directed system determined by the functor `I`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_diagram (I : D ⥤ ideal R) (i : ℕ) : Module.{max u v} R ⥤ Module.{max u v} R
colimit (diagram.{(max u v) v} I i)
def
local_cohomology.of_diagram
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[ "ideal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diagram_comp (i : ℕ) : diagram (I' ⋙ I) i ≅ I'.op ⋙ (diagram I i)
iso.refl _
def
local_cohomology.diagram_comp
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[]
Local cohomology along a composition of diagrams.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iso_of_final [functor.initial I'] (i : ℕ) : of_diagram.{(max u v) v'} (I' ⋙ I) i ≅ of_diagram.{(max u v') v} I i
(has_colimit.iso_of_nat_iso (diagram_comp _ _ _)) ≪≫ (functor.final.colimit_iso _ _)
def
local_cohomology.iso_of_final
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[]
Local cohomology agrees along precomposition with a cofinal diagram.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal_powers_diagram (J : ideal R) : ℕᵒᵖ ⥤ ideal R
{ obj := λ t, J^(unop t), map := λ s t w, ⟨⟨ideal.pow_le_pow w.unop.down.down⟩⟩, }
def
local_cohomology.ideal_powers_diagram
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[ "ideal" ]
The functor sending a natural number `i` to the `i`-th power of the ideal `J`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
self_le_radical (J : ideal R) : Type u
full_subcategory (λ J' : ideal R, J ≤ J'.radical)
def
local_cohomology.self_le_radical
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[ "ideal" ]
The full subcategory of all ideals with radical containing `J`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
self_le_radical.inhabited (J : ideal R) : inhabited (self_le_radical J)
{ default := ⟨J, ideal.le_radical⟩ }
instance
local_cohomology.self_le_radical.inhabited
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[ "ideal" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
self_le_radical_diagram (J : ideal R) : (self_le_radical J) ⥤ ideal R
full_subcategory_inclusion _
def
local_cohomology.self_le_radical_diagram
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[ "ideal" ]
The diagram of all ideals with radical containing `J`, represented as a functor. This is the "largest" diagram that computes local cohomology with support in `J`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
local_cohomology (J : ideal R) (i : ℕ) : Module.{u} R ⥤ Module.{u} R
of_diagram (ideal_powers_diagram J) i
def
local_cohomology
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[ "ideal" ]
`local_cohomology J i` is `i`-th the local cohomology module of a module `M` over a commutative ring `R` with support in the ideal `J` of `R`, defined as the direct limit of `Ext^i(R/J^t, M)` over all powers `t : ℕ`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
local_cohomology.of_self_le_radical (J : ideal R) (i : ℕ) : Module.{u} R ⥤ Module.{u} R
of_diagram.{u} (self_le_radical_diagram.{u} J) i
def
local_cohomology.of_self_le_radical
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[ "ideal" ]
Local cohomology as the direct limit of `Ext^i(R/J', M)` over *all* ideals `J'` with radical containing `J`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal_powers_to_self_le_radical (J : ideal R) : ℕᵒᵖ ⥤ self_le_radical J
full_subcategory.lift _ (ideal_powers_diagram J) (λ k, begin change _ ≤ (J^(unop k)).radical, cases (unop k), { simp only [ideal.radical_top, pow_zero, ideal.one_eq_top, le_top] }, { simp only [J.radical_pow _ n.succ_pos, ideal.le_radical] }, end)
def
local_cohomology.ideal_powers_to_self_le_radical
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[ "ideal", "ideal.le_radical", "ideal.one_eq_top", "ideal.radical_top", "le_top", "pow_zero" ]
Lifting `ideal_powers_diagram J` from a diagram valued in `ideals R` to a diagram valued in `self_le_radical J`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal.exists_pow_le_of_le_radical_of_fg (hIJ : I ≤ J.radical) (hJ : J.radical.fg) : ∃ (k : ℕ), I^k ≤ J
begin obtain ⟨k, hk⟩ := J.exists_radical_pow_le_of_fg hJ, use k, calc I^k ≤ J.radical^k : ideal.pow_mono hIJ _ ... ≤ J : hk, end
lemma
local_cohomology.ideal.exists_pow_le_of_le_radical_of_fg
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[ "ideal.pow_mono" ]
PORTING NOTE: This lemma should probably be moved to `ring_theory/finiteness.lean` to be near `ideal.exists_radical_pow_le_of_fg`, which it generalizes.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ideal_powers_initial [hR : is_noetherian R R] : functor.initial (ideal_powers_to_self_le_radical J)
{ out := λ J', begin apply @zigzag_is_connected _ _ _, { intros j1 j2, apply relation.refl_trans_gen.single, -- The inclusions `J^n1 ≤ J'` and `J^n2 ≤ J'` always form a triangle, based on -- which exponent is larger. cases le_total (unop j1.left) (unop j2.left) with h, right, exact ⟨costructur...
instance
local_cohomology.ideal_powers_initial
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[ "is_noetherian", "relation.refl_trans_gen.single" ]
The diagram of powers of `J` is initial in the diagram of all ideals with radical containing `J`. This uses noetherianness.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iso_self_le_radical (J : ideal R) [is_noetherian R R] (i : ℕ) : local_cohomology.of_self_le_radical J i ≅ local_cohomology J i
(local_cohomology.iso_of_final.{u u 0} (ideal_powers_to_self_le_radical J) (self_le_radical_diagram J) i).symm ≪≫ has_colimit.iso_of_nat_iso (iso.refl _)
def
local_cohomology.iso_self_le_radical
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[ "ideal", "is_noetherian", "local_cohomology", "local_cohomology.of_self_le_radical" ]
Local cohomology (defined in terms of powers of `J`) agrees with local cohomology computed over all ideals with radical containing `J`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
self_le_radical.cast (hJK : J.radical = K.radical) : self_le_radical J ⥤ self_le_radical K
full_subcategory.map (λ L hL, begin rw ← ideal.radical_le_radical_iff at ⊢ hL, exact hJK.symm.trans_le hL, end)
def
local_cohomology.self_le_radical.cast
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[ "ideal.radical_le_radical_iff" ]
Casting from the full subcategory of ideals with radical containing `J` to the full subcategory of ideals with radical containing `K`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
self_le_radical.cast_is_equivalence (hJK : J.radical = K.radical) : is_equivalence (self_le_radical.cast hJK)
{ inverse := self_le_radical.cast hJK.symm, unit_iso := by tidy, counit_iso := by tidy }
instance
local_cohomology.self_le_radical.cast_is_equivalence
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
self_le_radical.iso_of_same_radical (hJK : J.radical = K.radical) (i : ℕ) : of_self_le_radical J i ≅ of_self_le_radical K i
(iso_of_final.{u u u} (self_le_radical.cast hJK.symm) _ _).symm
def
local_cohomology.self_le_radical.iso_of_same_radical
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[]
The natural isomorphism between local cohomology defined using the `of_self_le_radical` diagram, assuming `J.radical = K.radical`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iso_of_same_radical [is_noetherian R R] (hJK : J.radical = K.radical) (i : ℕ) : local_cohomology J i ≅ local_cohomology K i
(iso_self_le_radical J i).symm ≪≫ self_le_radical.iso_of_same_radical hJK i ≪≫ iso_self_le_radical K i
def
local_cohomology.iso_of_same_radical
algebra.homology
src/algebra/homology/local_cohomology.lean
[ "ring_theory.ideal.basic", "algebra.category.Module.colimits", "algebra.category.Module.projective", "category_theory.abelian.ext", "category_theory.limits.final", "ring_theory.noetherian" ]
[ "is_noetherian", "local_cohomology" ]
Local cohomology agrees on ideals with the same radical.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology_ext {L M N K : Module R} {f : L ⟶ M} {g : M ⟶ N} (w : f ≫ g = 0) {h k : homology f g w ⟶ K} (w : ∀ (x : linear_map.ker g), h (cokernel.π (image_to_kernel _ _ w) (to_kernel_subobject x)) = k (cokernel.π (image_to_kernel _ _ w) (to_kernel_subobject x))) : h = k
begin refine cokernel_funext (λ n, _), -- Gosh it would be nice if `equiv_rw` could directly use an isomorphism, or an enriched `≃`. equiv_rw (kernel_subobject_iso g ≪≫ Module.kernel_iso_ker g).to_linear_equiv.to_equiv at n, convert w n; simp [to_kernel_subobject], end
lemma
Module.homology_ext
algebra.homology
src/algebra/homology/Module.lean
[ "algebra.homology.homotopy", "algebra.category.Module.abelian", "algebra.category.Module.subobject", "category_theory.limits.concrete_category" ]
[ "Module", "Module.kernel_iso_ker", "homology", "image_to_kernel", "linear_map.ker" ]
To prove that two maps out of a homology group are equal, it suffices to check they are equal on the images of cycles.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_cycles {C : homological_complex (Module.{u} R) c} {i : ι} (x : linear_map.ker (C.d_from i)) : C.cycles i
to_kernel_subobject x
abbreviation
Module.to_cycles
algebra.homology
src/algebra/homology/Module.lean
[ "algebra.homology.homotopy", "algebra.category.Module.abelian", "algebra.category.Module.subobject", "category_theory.limits.concrete_category" ]
[ "homological_complex", "linear_map.ker" ]
Bundle an element `C.X i` such that `C.d_from i x = 0` as a term of `C.cycles i`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cycles_ext {C : homological_complex (Module.{u} R) c} {i : ι} {x y : C.cycles i} (w : (C.cycles i).arrow x = (C.cycles i).arrow y) : x = y
begin apply_fun (C.cycles i).arrow using (Module.mono_iff_injective _).mp (cycles C i).arrow_mono, exact w, end
lemma
Module.cycles_ext
algebra.homology
src/algebra/homology/Module.lean
[ "algebra.homology.homotopy", "algebra.category.Module.abelian", "algebra.category.Module.subobject", "category_theory.limits.concrete_category" ]
[ "Module.mono_iff_injective", "homological_complex" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cycles_map_to_cycles (f : C ⟶ D) {i : ι} (x : linear_map.ker (C.d_from i)) : (cycles_map f i) (to_cycles x) = to_cycles ⟨f.f i x.1, by simp [x.2]⟩
by { ext, simp, }
lemma
Module.cycles_map_to_cycles
algebra.homology
src/algebra/homology/Module.lean
[ "algebra.homology.homotopy", "algebra.category.Module.abelian", "algebra.category.Module.subobject", "category_theory.limits.concrete_category" ]
[ "cycles_map", "linear_map.ker" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_homology {C : homological_complex (Module.{u} R) c} {i : ι} (x : linear_map.ker (C.d_from i)) : C.homology i
homology.π (C.d_to i) (C.d_from i) _ (to_cycles x)
abbreviation
Module.to_homology
algebra.homology
src/algebra/homology/Module.lean
[ "algebra.homology.homotopy", "algebra.category.Module.abelian", "algebra.category.Module.subobject", "category_theory.limits.concrete_category" ]
[ "homological_complex", "homology.π", "linear_map.ker" ]
Build a term of `C.homology i` from an element `C.X i` such that `C.d_from i x = 0`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology_ext' {M : Module R} (i : ι) {h k : C.homology i ⟶ M} (w : ∀ (x : linear_map.ker (C.d_from i)), h (to_homology x) = k (to_homology x)) : h = k
homology_ext _ w
lemma
Module.homology_ext'
algebra.homology
src/algebra/homology/Module.lean
[ "algebra.homology.homotopy", "algebra.category.Module.abelian", "algebra.category.Module.subobject", "category_theory.limits.concrete_category" ]
[ "Module", "linear_map.ker" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image_to_kernel_op {X Y Z : V} (f : X ⟶ Y) (g : Y ⟶ Z) (w : f ≫ g = 0) : image_to_kernel g.op f.op (by rw [←op_comp, w, op_zero]) = ((image_subobject_iso _) ≪≫ (image_op_op _).symm).hom ≫ (cokernel.desc f (factor_thru_image g) (by rw [←cancel_mono (image.ι g), category.assoc, image.fac, w, zero_comp])).op ≫ (...
begin ext, simpa only [iso.trans_hom, iso.symm_hom, iso.trans_inv, kernel_op_op_inv, category.assoc, image_to_kernel_arrow, kernel_subobject_arrow', kernel.lift_ι, ←op_comp, cokernel.π_desc, ←image_subobject_arrow, ←image_unop_op_inv_comp_op_factor_thru_image g.op], end
lemma
image_to_kernel_op
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "image_to_kernel", "image_to_kernel_arrow" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
image_to_kernel_unop {X Y Z : Vᵒᵖ} (f : X ⟶ Y) (g : Y ⟶ Z) (w : f ≫ g = 0) : image_to_kernel g.unop f.unop (by rw [←unop_comp, w, unop_zero]) = ((image_subobject_iso _) ≪≫ (image_unop_unop _).symm).hom ≫ (cokernel.desc f (factor_thru_image g) (by rw [←cancel_mono (image.ι g), category.assoc, image.fac, w, zero_...
begin ext, dunfold image_unop_unop, simp only [iso.trans_hom, iso.symm_hom, iso.trans_inv, kernel_unop_unop_inv, category.assoc, image_to_kernel_arrow, kernel_subobject_arrow', kernel.lift_ι, cokernel.π_desc, iso.unop_inv, ←unop_comp, factor_thru_image_comp_image_unop_op_inv, quiver.hom.unop_op, image...
lemma
image_to_kernel_unop
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "image_to_kernel", "image_to_kernel_arrow", "quiver.hom.unop_op" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology_op {X Y Z : V} (f : X ⟶ Y) (g : Y ⟶ Z) (w : f ≫ g = 0) : homology g.op f.op (by rw [←op_comp, w, op_zero]) ≅ opposite.op (homology f g w)
cokernel_iso_of_eq (image_to_kernel_op _ _ w) ≪≫ (cokernel_epi_comp _ _) ≪≫ cokernel_comp_is_iso _ _ ≪≫ cokernel_op_op _ ≪≫ ((homology_iso_kernel_desc _ _ _) ≪≫ (kernel_iso_of_eq (by ext; simp only [image.fac, cokernel.π_desc, cokernel.π_desc_assoc])) ≪≫ (kernel_comp_mono _ (image.ι g))).op
def
homology_op
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homology", "homology_iso_kernel_desc", "image_to_kernel_op", "opposite.op" ]
Given `f, g` with `f ≫ g = 0`, the homology of `g.op, f.op` is the opposite of the homology of `f, g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology_unop {X Y Z : Vᵒᵖ} (f : X ⟶ Y) (g : Y ⟶ Z) (w : f ≫ g = 0) : homology g.unop f.unop (by rw [←unop_comp, w, unop_zero]) ≅ opposite.unop (homology f g w)
cokernel_iso_of_eq (image_to_kernel_unop _ _ w) ≪≫ (cokernel_epi_comp _ _) ≪≫ cokernel_comp_is_iso _ _ ≪≫ cokernel_unop_unop _ ≪≫ ((homology_iso_kernel_desc _ _ _) ≪≫ (kernel_iso_of_eq (by ext; simp only [image.fac, cokernel.π_desc, cokernel.π_desc_assoc])) ≪≫ (kernel_comp_mono _ (image.ι g))).unop
def
homology_unop
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homology", "homology_iso_kernel_desc", "image_to_kernel_unop", "opposite.unop" ]
Given morphisms `f, g` in `Vᵒᵖ` with `f ≫ g = 0`, the homology of `g.unop, f.unop` is the opposite of the homology of `f, g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
op (X : homological_complex V c) : homological_complex Vᵒᵖ c.symm
{ X := λ i, op (X.X i), d := λ i j, (X.d j i).op, shape' := λ i j hij, by { rw [X.shape j i hij, op_zero], }, d_comp_d' := by { intros, rw [← op_comp, X.d_comp_d, op_zero], } }
def
homological_complex.op
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex" ]
Sends a complex `X` with objects in `V` to the corresponding complex with objects in `Vᵒᵖ`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
op_symm (X : homological_complex V c.symm) : homological_complex Vᵒᵖ c
{ X := λ i, op (X.X i), d := λ i j, (X.d j i).op, shape' := λ i j hij, by { rw [X.shape j i hij, op_zero], }, d_comp_d' := by { intros, rw [← op_comp, X.d_comp_d, op_zero], } }
def
homological_complex.op_symm
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex" ]
Sends a complex `X` with objects in `V` to the corresponding complex with objects in `Vᵒᵖ`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unop (X : homological_complex Vᵒᵖ c) : homological_complex V c.symm
{ X := λ i, unop (X.X i), d := λ i j, (X.d j i).unop, shape' := λ i j hij, by { rw [X.shape j i hij, unop_zero], }, d_comp_d' := by { intros, rw [← unop_comp, X.d_comp_d, unop_zero], } }
def
homological_complex.unop
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex" ]
Sends a complex `X` with objects in `Vᵒᵖ` to the corresponding complex with objects in `V`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unop_symm (X : homological_complex Vᵒᵖ c.symm) : homological_complex V c
{ X := λ i, unop (X.X i), d := λ i j, (X.d j i).unop, shape' := λ i j hij, by { rw [X.shape j i hij, unop_zero], }, d_comp_d' := by { intros, rw [← unop_comp, X.d_comp_d, unop_zero], } }
def
homological_complex.unop_symm
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex" ]
Sends a complex `X` with objects in `Vᵒᵖ` to the corresponding complex with objects in `V`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
op_functor : (homological_complex V c)ᵒᵖ ⥤ homological_complex Vᵒᵖ c.symm
{ obj := λ X, (unop X).op, map := λ X Y f, { f := λ i, (f.unop.f i).op, comm' := λ i j hij, by simp only [op_d, ← op_comp, f.unop.comm] }, }
def
homological_complex.op_functor
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex" ]
Auxilliary definition for `op_equivalence`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
op_inverse : homological_complex Vᵒᵖ c.symm ⥤ (homological_complex V c)ᵒᵖ
{ obj := λ X, op X.unop_symm, map := λ X Y f, quiver.hom.op { f := λ i, (f.f i).unop, comm' := λ i j hij, by simp only [unop_symm_d, ←unop_comp, f.comm], }}
def
homological_complex.op_inverse
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex", "quiver.hom.op" ]
Auxilliary definition for `op_equivalence`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
op_unit_iso : 𝟭 (homological_complex V c)ᵒᵖ ≅ op_functor V c ⋙ op_inverse V c
nat_iso.of_components (λ X, (homological_complex.hom.iso_of_components (λ i, iso.refl _) (λ i j hij, by simp only [iso.refl_hom, category.id_comp, unop_symm_d, op_d, quiver.hom.unop_op, category.comp_id]) : (opposite.unop X).op.unop_symm ≅ unop X).op) begin intros X Y f, refine quiver.hom.unop_inj _...
def
homological_complex.op_unit_iso
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex", "homological_complex.hom.iso_of_components", "opposite.unop", "quiver.hom.unop_inj", "quiver.hom.unop_op" ]
Auxilliary definition for `op_equivalence`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
op_counit_iso : op_inverse V c ⋙ op_functor V c ≅ 𝟭 (homological_complex Vᵒᵖ c.symm)
nat_iso.of_components (λ X, homological_complex.hom.iso_of_components (λ i, iso.refl _) (λ i j hij, by simpa only [iso.refl_hom, category.id_comp, category.comp_id])) begin intros X Y f, ext, simpa only [quiver.hom.unop_op, quiver.hom.op_unop, functor.comp_map, functor.id_map, iso.refl_hom, catego...
def
homological_complex.op_counit_iso
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex", "homological_complex.hom.iso_of_components", "quiver.hom.op_unop", "quiver.hom.unop_op" ]
Auxilliary definition for `op_equivalence`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
op_equivalence : (homological_complex V c)ᵒᵖ ≌ homological_complex Vᵒᵖ c.symm
{ functor := op_functor V c, inverse := op_inverse V c, unit_iso := op_unit_iso V c, counit_iso := op_counit_iso V c, functor_unit_iso_comp' := begin intro X, ext, simp only [op_unit_iso, op_counit_iso, nat_iso.of_components_hom_app, iso.op_hom, comp_f, op_functor_map_f, quiver.hom.unop_op, ...
def
homological_complex.op_equivalence
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex", "quiver.hom.unop_op" ]
Given a category of complexes with objects in `V`, there is a natural equivalence between its opposite category and a category of complexes with objects in `Vᵒᵖ`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unop_functor : (homological_complex Vᵒᵖ c)ᵒᵖ ⥤ homological_complex V c.symm
{ obj := λ X, (unop X).unop, map := λ X Y f, { f := λ i, (f.unop.f i).unop, comm' := λ i j hij, by simp only [unop_d, ← unop_comp, f.unop.comm] }, }
def
homological_complex.unop_functor
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex" ]
Auxilliary definition for `unop_equivalence`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unop_inverse : homological_complex V c.symm ⥤ (homological_complex Vᵒᵖ c)ᵒᵖ
{ obj := λ X, op X.op_symm, map := λ X Y f, quiver.hom.op { f := λ i, (f.f i).op, comm' := λ i j hij, by simp only [op_symm_d, ←op_comp, f.comm], }}
def
homological_complex.unop_inverse
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex", "quiver.hom.op" ]
Auxilliary definition for `unop_equivalence`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unop_unit_iso : 𝟭 (homological_complex Vᵒᵖ c)ᵒᵖ ≅ unop_functor V c ⋙ unop_inverse V c
nat_iso.of_components (λ X, (homological_complex.hom.iso_of_components (λ i, iso.refl _) (λ i j hij, by simp only [iso.refl_hom, category.id_comp, unop_symm_d, op_d, quiver.hom.unop_op, category.comp_id]) : (opposite.unop X).op.unop_symm ≅ unop X).op) begin intros X Y f, refine quiver.hom.unop_inj _...
def
homological_complex.unop_unit_iso
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex", "homological_complex.hom.iso_of_components", "opposite.unop", "quiver.hom.unop_inj", "quiver.hom.unop_op" ]
Auxilliary definition for `unop_equivalence`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unop_counit_iso : unop_inverse V c ⋙ unop_functor V c ≅ 𝟭 (homological_complex V c.symm)
nat_iso.of_components (λ X, homological_complex.hom.iso_of_components (λ i, iso.refl _) (λ i j hij, by simpa only [iso.refl_hom, category.id_comp, category.comp_id])) begin intros X Y f, ext, simpa only [quiver.hom.unop_op, quiver.hom.op_unop, functor.comp_map, functor.id_map, iso.refl_hom, catego...
def
homological_complex.unop_counit_iso
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex", "homological_complex.hom.iso_of_components", "quiver.hom.op_unop", "quiver.hom.unop_op" ]
Auxilliary definition for `unop_equivalence`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unop_equivalence : (homological_complex Vᵒᵖ c)ᵒᵖ ≌ homological_complex V c.symm
{ functor := unop_functor V c, inverse := unop_inverse V c, unit_iso := unop_unit_iso V c, counit_iso := unop_counit_iso V c, functor_unit_iso_comp' := begin intro X, ext, simp only [op_unit_iso, op_counit_iso, nat_iso.of_components_hom_app, iso.op_hom, comp_f, op_functor_map_f, quiver.hom.u...
def
homological_complex.unop_equivalence
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex", "quiver.hom.unop_op" ]
Given a category of complexes with objects in `Vᵒᵖ`, there is a natural equivalence between its opposite category and a category of complexes with objects in `V`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
op_functor_additive : (@op_functor ι V _ c _).additive
{}
instance
homological_complex.op_functor_additive
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "additive" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unop_functor_additive : (@unop_functor ι V _ c _).additive
{}
instance
homological_complex.unop_functor_additive
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "additive" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology_op_def : C.op.homology i ≅ _root_.homology (C.d_from i).op (C.d_to i).op (by rw [←op_comp, C.d_to_comp_d_from i, op_zero])
iso.refl _
def
homological_complex.homology_op_def
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[]
Auxilliary tautological definition for `homology_op`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology_op : C.op.homology i ≅ opposite.op (C.homology i)
homology_op_def _ _ ≪≫ homology_op _ _ _
def
homological_complex.homology_op
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homology_op", "opposite.op" ]
Given a complex `C` of objects in `V`, the `i`th homology of its 'opposite' complex (with objects in `Vᵒᵖ`) is the opposite of the `i`th homology of `C`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology_unop_def (C : homological_complex Vᵒᵖ c) : C.unop.homology i ≅ _root_.homology (C.d_from i).unop (C.d_to i).unop (by rw [←unop_comp, C.d_to_comp_d_from i, unop_zero])
iso.refl _
def
homological_complex.homology_unop_def
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex" ]
Auxilliary tautological definition for `homology_unop`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
homology_unop (C : homological_complex Vᵒᵖ c) : C.unop.homology i ≅ opposite.unop (C.homology i)
homology_unop_def _ _ ≪≫ homology_unop _ _ _
def
homological_complex.homology_unop
algebra.homology
src/algebra/homology/opposite.lean
[ "category_theory.abelian.opposite", "category_theory.abelian.homology", "algebra.homology.additive" ]
[ "homological_complex", "homology_unop", "opposite.unop" ]
Given a complex `C` of objects in `Vᵒᵖ`, the `i`th homology of its 'opposite' complex (with objects in `V`) is the opposite of the `i`th homology of `C`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quasi_iso (f : C ⟶ D) : Prop
(is_iso : ∀ i, is_iso ((homology_functor V c i).map f))
class
quasi_iso
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "homology_functor" ]
A chain map is a quasi-isomorphism if it induces isomorphisms on homology.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quasi_iso_of_iso (f : C ⟶ D) [is_iso f] : quasi_iso f
{ is_iso := λ i, begin change is_iso (((homology_functor V c i).map_iso (as_iso f)).hom), apply_instance, end }
instance
quasi_iso_of_iso
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "homology_functor", "quasi_iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quasi_iso_comp (f : C ⟶ D) [quasi_iso f] (g : D ⟶ E) [quasi_iso g] : quasi_iso (f ≫ g)
{ is_iso := λ i, begin rw functor.map_comp, apply_instance, end }
instance
quasi_iso_comp
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "quasi_iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quasi_iso_of_comp_left (f : C ⟶ D) [quasi_iso f] (g : D ⟶ E) [quasi_iso (f ≫ g)] : quasi_iso g
{ is_iso := λ i, is_iso.of_is_iso_fac_left ((homology_functor V c i).map_comp f g).symm }
lemma
quasi_iso_of_comp_left
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "homology_functor", "map_comp", "quasi_iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
quasi_iso_of_comp_right (f : C ⟶ D) (g : D ⟶ E) [quasi_iso g] [quasi_iso (f ≫ g)] : quasi_iso f
{ is_iso := λ i, is_iso.of_is_iso_fac_right ((homology_functor V c i).map_comp f g).symm }
lemma
quasi_iso_of_comp_right
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "homology_functor", "map_comp", "quasi_iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_quasi_iso {C D : homological_complex W c} (e : homotopy_equiv C D) : quasi_iso e.hom
⟨λ i, begin refine ⟨⟨(homology_functor W c i).map e.inv, _⟩⟩, simp only [← functor.map_comp, ← (homology_functor W c i).map_id], split; apply homology_map_eq_of_homotopy, exacts [e.homotopy_hom_inv_id, e.homotopy_inv_hom_id], end⟩
lemma
homotopy_equiv.to_quasi_iso
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "homological_complex", "homology_functor", "homology_map_eq_of_homotopy", "homotopy_equiv", "map_id", "quasi_iso" ]
An homotopy equivalence is a quasi-isomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_quasi_iso_inv {C D : homological_complex W c} (e : homotopy_equiv C D) (i : ι) : (@as_iso _ _ _ _ _ (e.to_quasi_iso.1 i)).inv = (homology_functor W c i).map e.inv
begin symmetry, simp only [←iso.hom_comp_eq_id, as_iso_hom, ←functor.map_comp, ←(homology_functor W c i).map_id, homology_map_eq_of_homotopy e.homotopy_hom_inv_id _], end
lemma
homotopy_equiv.to_quasi_iso_inv
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "homological_complex", "homology_functor", "homology_map_eq_of_homotopy", "homotopy_equiv", "map_id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_single₀_cokernel_at_zero_iso : cokernel (X.d 1 0) ≅ Y
(X.homology_zero_iso.symm.trans ((@as_iso _ _ _ _ _ (hf.1 0)).trans ((chain_complex.homology_functor_0_single₀ W).app Y)))
def
homological_complex.hom.to_single₀_cokernel_at_zero_iso
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "chain_complex.homology_functor_0_single₀" ]
If a chain map `f : X ⟶ Y[0]` is a quasi-isomorphism, then the cokernel of the differential `d : X₁ → X₀` is isomorphic to `Y.`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_single₀_cokernel_at_zero_iso_hom_eq [hf : quasi_iso f] : f.to_single₀_cokernel_at_zero_iso.hom = cokernel.desc (X.d 1 0) (f.f 0) (by rw ←f.2 1 0 rfl; exact comp_zero)
begin ext, dunfold to_single₀_cokernel_at_zero_iso chain_complex.homology_zero_iso homology_of_zero_right homology.map_iso chain_complex.homology_functor_0_single₀ cokernel.map, dsimp, simp only [cokernel.π_desc, category.assoc, homology.map_desc, cokernel.π_desc_assoc], simp [homology.desc, iso.refl_inv ...
lemma
homological_complex.hom.to_single₀_cokernel_at_zero_iso_hom_eq
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "chain_complex.homology_functor_0_single₀", "chain_complex.homology_zero_iso", "homology.desc", "homology.map_desc", "homology.map_iso", "homology_of_zero_right", "quasi_iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_single₀_epi_at_zero [hf : quasi_iso f] : epi (f.f 0)
begin constructor, intros Z g h Hgh, rw [←cokernel.π_desc (X.d 1 0) (f.f 0) (by rw ←f.2 1 0 rfl; exact comp_zero), ←to_single₀_cokernel_at_zero_iso_hom_eq] at Hgh, rw (@cancel_epi _ _ _ _ _ _ (epi_comp _ _) _ _).1 Hgh, end
lemma
homological_complex.hom.to_single₀_epi_at_zero
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "quasi_iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_single₀_exact_d_f_at_zero [hf : quasi_iso f] : exact (X.d 1 0) (f.f 0)
begin rw preadditive.exact_iff_homology_zero, have h : X.d 1 0 ≫ f.f 0 = 0, { simp only [← f.2 1 0 rfl, chain_complex.single₀_obj_X_d, comp_zero], }, refine ⟨h, nonempty.intro (homology_iso_kernel_desc _ _ _ ≪≫ _)⟩, { suffices : is_iso (cokernel.desc _ _ h), { haveI := this, apply kernel.of_mono, }, ...
lemma
homological_complex.hom.to_single₀_exact_d_f_at_zero
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "chain_complex.single₀_obj_X_d", "homology_iso_kernel_desc", "quasi_iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_single₀_exact_at_succ [hf : quasi_iso f] (n : ℕ) : exact (X.d (n + 2) (n + 1)) (X.d (n + 1) n)
(preadditive.exact_iff_homology_zero _ _).2 ⟨X.d_comp_d _ _ _, ⟨(chain_complex.homology_succ_iso _ _).symm.trans ((@as_iso _ _ _ _ _ (hf.1 (n + 1))).trans homology_zero_zero)⟩⟩
lemma
homological_complex.hom.to_single₀_exact_at_succ
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "chain_complex.homology_succ_iso", "homology_zero_zero", "quasi_iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
from_single₀_kernel_at_zero_iso [hf : quasi_iso f] : kernel (X.d 0 1) ≅ Y
(X.homology_zero_iso.symm.trans ((@as_iso _ _ _ _ _ (hf.1 0)).symm.trans ((cochain_complex.homology_functor_0_single₀ W).app Y)))
def
homological_complex.hom.from_single₀_kernel_at_zero_iso
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "cochain_complex.homology_functor_0_single₀", "quasi_iso" ]
If a cochain map `f : Y[0] ⟶ X` is a quasi-isomorphism, then the kernel of the differential `d : X₀ → X₁` is isomorphic to `Y.`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
from_single₀_kernel_at_zero_iso_inv_eq [hf : quasi_iso f] : f.from_single₀_kernel_at_zero_iso.inv = kernel.lift (X.d 0 1) (f.f 0) (by rw f.2 0 1 rfl; exact zero_comp)
begin ext, dunfold from_single₀_kernel_at_zero_iso cochain_complex.homology_zero_iso homology_of_zero_left homology.map_iso cochain_complex.homology_functor_0_single₀ kernel.map, simp only [iso.trans_inv, iso.app_inv, iso.symm_inv, category.assoc, equalizer_as_kernel, kernel.lift_ι], dsimp, simp only ...
lemma
homological_complex.hom.from_single₀_kernel_at_zero_iso_inv_eq
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "cochain_complex.homology_functor_0_single₀", "cochain_complex.homology_zero_iso", "homology.map_iso", "homology.π", "homology.π_map", "homology_of_zero_left", "quasi_iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
from_single₀_mono_at_zero [hf : quasi_iso f] : mono (f.f 0)
begin constructor, intros Z g h Hgh, rw [←kernel.lift_ι (X.d 0 1) (f.f 0) (by rw f.2 0 1 rfl; exact zero_comp), ←from_single₀_kernel_at_zero_iso_inv_eq] at Hgh, rw (@cancel_mono _ _ _ _ _ _ (mono_comp _ _) _ _).1 Hgh, end
lemma
homological_complex.hom.from_single₀_mono_at_zero
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "quasi_iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
from_single₀_exact_f_d_at_zero [hf : quasi_iso f] : exact (f.f 0) (X.d 0 1)
begin rw preadditive.exact_iff_homology_zero, have h : f.f 0 ≫ X.d 0 1 = 0, { simp only [homological_complex.hom.comm, cochain_complex.single₀_obj_X_d, zero_comp] }, refine ⟨h, nonempty.intro (homology_iso_cokernel_lift _ _ _ ≪≫ _)⟩, { suffices : is_iso (kernel.lift (X.d 0 1) (f.f 0) h), { haveI := this, ...
lemma
homological_complex.hom.from_single₀_exact_f_d_at_zero
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "cochain_complex.single₀_obj_X_d", "homological_complex.hom.comm", "homology_iso_cokernel_lift", "quasi_iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
from_single₀_exact_at_succ [hf : quasi_iso f] (n : ℕ) : exact (X.d n (n + 1)) (X.d (n + 1) (n + 2))
(preadditive.exact_iff_homology_zero _ _).2 ⟨X.d_comp_d _ _ _, ⟨(cochain_complex.homology_succ_iso _ _).symm.trans ((@as_iso _ _ _ _ _ (hf.1 (n + 1))).symm.trans homology_zero_zero)⟩⟩
lemma
homological_complex.hom.from_single₀_exact_at_succ
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "cochain_complex.homology_succ_iso", "homology_zero_zero", "quasi_iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
category_theory.functor.quasi_iso_of_map_quasi_iso {C D : homological_complex A c} (f : C ⟶ D) (hf : quasi_iso ((F.map_homological_complex _).map f)) : quasi_iso f
⟨λ i, begin haveI : is_iso (F.map ((homology_functor A c i).map f)), { rw [← functor.comp_map, ← nat_iso.naturality_2 (F.homology_functor_iso i) f, functor.comp_map], apply_instance, }, exact is_iso_of_reflects_iso _ F, end⟩
lemma
category_theory.functor.quasi_iso_of_map_quasi_iso
algebra.homology
src/algebra/homology/quasi_iso.lean
[ "algebra.homology.homotopy", "category_theory.abelian.homology" ]
[ "homological_complex", "homology_functor", "quasi_iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
single (j : ι) : V ⥤ homological_complex V c
{ obj := λ A, { X := λ i, if i = j then A else 0, d := λ i j, 0, }, map := λ A B f, { f := λ i, if h : i = j then eq_to_hom (by { dsimp, rw if_pos h, }) ≫ f ≫ eq_to_hom (by { dsimp, rw if_pos h, }) else 0, }, map_id' := λ A, begin ext, dsimp, split_ifs with h, { subst h, simp...
def
homological_complex.single
algebra.homology
src/algebra/homology/single.lean
[ "algebra.homology.homology" ]
[ "homological_complex" ]
The functor `V ⥤ homological_complex V c` creating a chain complex supported in a single degree. See also `chain_complex.single₀ : V ⥤ chain_complex V ℕ`, which has better definitional properties, if you are working with `ℕ`-indexed complexes.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
single_obj_X_self (j : ι) (A : V) : ((single V c j).obj A).X j ≅ A
eq_to_iso (by simp)
def
homological_complex.single_obj_X_self
algebra.homology
src/algebra/homology/single.lean
[ "algebra.homology.homology" ]
[]
The object in degree `j` of `(single V c h).obj A` is just `A`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
single_map_f_self (j : ι) {A B : V} (f : A ⟶ B) : ((single V c j).map f).f j = (single_obj_X_self V c j A).hom ≫ f ≫ (single_obj_X_self V c j B).inv
by { simp, refl, }
lemma
homological_complex.single_map_f_self
algebra.homology
src/algebra/homology/single.lean
[ "algebra.homology.homology" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
single₀ : V ⥤ chain_complex V ℕ
{ obj := λ X, { X := λ n, match n with | 0 := X | (n+1) := 0 end, d := λ i j, 0, }, map := λ X Y f, { f := λ n, match n with | 0 := f | (n+1) := 0 end, }, map_id' := λ X, by { ext n, cases n, refl, dsimp, unfold_aux, simp, }, map_comp' := λ X Y Z f g, by { ext n, cases n, refl, dsi...
def
chain_complex.single₀
algebra.homology
src/algebra/homology/single.lean
[ "algebra.homology.homology" ]
[ "chain_complex" ]
`chain_complex.single₀ V` is the embedding of `V` into `chain_complex V ℕ` as chain complexes supported in degree 0. This is naturally isomorphic to `single V _ 0`, but has better definitional properties.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
single₀_obj_X_0 (X : V) : ((single₀ V).obj X).X 0 = X
rfl
lemma
chain_complex.single₀_obj_X_0
algebra.homology
src/algebra/homology/single.lean
[ "algebra.homology.homology" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
single₀_obj_X_succ (X : V) (n : ℕ) : ((single₀ V).obj X).X (n+1) = 0
rfl
lemma
chain_complex.single₀_obj_X_succ
algebra.homology
src/algebra/homology/single.lean
[ "algebra.homology.homology" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
single₀_obj_X_d (X : V) (i j : ℕ) : ((single₀ V).obj X).d i j = 0
rfl
lemma
chain_complex.single₀_obj_X_d
algebra.homology
src/algebra/homology/single.lean
[ "algebra.homology.homology" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83