Functors which preserves homology #
If F : C ⥤ D is a functor between categories with zero morphisms, we shall
say that F preserves homology when F preserves both kernels and cokernels.
This typeclass is named [F.PreservesHomology], and is automatically
satisfied when F preserves both finite limits and finite colimits.
If S : ShortComplex C and [F.PreservesHomology], then there is an
isomorphism S.mapHomologyIso F : (S.map F).homology ≅ F.obj S.homology, which
is part of the natural isomorphism homologyFunctorIso F between the functors
F.mapShortComplex ⋙ homologyFunctor D and homologyFunctor C ⋙ F.
A functor preserves homology when it preserves both kernels and cokernels.
the functor preserves kernels
the functor preserves cokernels
Instances
A functor which preserves homology preserves kernels.
A functor which preserves homology preserves cokernels.
A left homology data h of a short complex S is preserved by a functor F is
F preserves the kernel of S.g : S.X₂ ⟶ S.X₃ and the cokernel of h.f' : S.X₁ ⟶ h.K.
- g : Limits.PreservesLimit (Limits.parallelPair S.g 0) F
the functor preserves the kernel of
S.g : S.X₂ ⟶ S.X₃. - f' : Limits.PreservesColimit (Limits.parallelPair h.f' 0) F
the functor preserves the cokernel of
h.f' : S.X₁ ⟶ h.K.
Instances
When a left homology data is preserved by a functor F, this functor
preserves the kernel of S.g : S.X₂ ⟶ S.X₃.
When a left homology data h is preserved by a functor F, this functor
preserves the cokernel of h.f' : S.X₁ ⟶ h.K.
When a left homology data h of a short complex S is preserved by a functor F,
this is the induced left homology data h.map F for the short complex S.map F.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Given a left homology map data ψ : LeftHomologyMapData φ h₁ h₂ such that
both left homology data h₁ and h₂ are preserved by a functor F, this is
the induced left homology map data for the morphism F.mapShortComplex.map φ.
Instances For
A right homology data h of a short complex S is preserved by a functor F is
F preserves the cokernel of S.f : S.X₁ ⟶ S.X₂ and the kernel of h.g' : h.Q ⟶ S.X₃.
- f : Limits.PreservesColimit (Limits.parallelPair S.f 0) F
the functor preserves the cokernel of
S.f : S.X₁ ⟶ S.X₂. - g' : Limits.PreservesLimit (Limits.parallelPair h.g' 0) F
the functor preserves the kernel of
h.g' : h.Q ⟶ S.X₃.
Instances
When a right homology data is preserved by a functor F, this functor
preserves the cokernel of S.f : S.X₁ ⟶ S.X₂.
When a right homology data h is preserved by a functor F, this functor
preserves the kernel of h.g' : h.Q ⟶ S.X₃.
When a right homology data h of a short complex S is preserved by a functor F,
this is the induced right homology data h.map F for the short complex S.map F.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Given a right homology map data ψ : RightHomologyMapData φ h₁ h₂ such that
both right homology data h₁ and h₂ are preserved by a functor F, this is
the induced right homology map data for the morphism F.mapShortComplex.map φ.
Instances For
When a homology data h of a short complex S is such that both h.left and
h.right are preserved by a functor F, this is the induced homology data
h.map F for the short complex S.map F.
Equations
Instances For
Given a homology map data ψ : HomologyMapData φ h₁ h₂ such that
h₁.left, h₁.right, h₂.left and h₂.right are all preserved by a functor F, this is
the induced homology map data for the morphism F.mapShortComplex.map φ.
Instances For
A functor preserves the left homology of a short complex S if it preserves all the
left homology data of S.
- isPreservedBy (h : S.LeftHomologyData) : h.IsPreservedBy F
the functor preserves all the left homology data of the short complex
Instances
A functor preserves the right homology of a short complex S if it preserves all the
right homology data of S.
- isPreservedBy (h : S.RightHomologyData) : h.IsPreservedBy F
the functor preserves all the right homology data of the short complex
Instances
If a functor preserves a certain left homology data of a short complex S, then it
preserves the left homology of S.
If a functor preserves a certain right homology data of a short complex S, then it
preserves the right homology of S.
When a functor F preserves the left homology of a short complex S, this is the
canonical isomorphism (S.map F).cycles ≅ F.obj S.cycles.
Equations
- S.mapCyclesIso F = (S.leftHomologyData.map F).cyclesIso
Instances For
When a functor F preserves the left homology of a short complex S, this is the
canonical isomorphism (S.map F).leftHomology ≅ F.obj S.leftHomology.
Equations
- S.mapLeftHomologyIso F = (S.leftHomologyData.map F).leftHomologyIso
Instances For
When a functor F preserves the right homology of a short complex S, this is the
canonical isomorphism (S.map F).opcycles ≅ F.obj S.opcycles.
Equations
- S.mapOpcyclesIso F = (S.rightHomologyData.map F).opcyclesIso
Instances For
When a functor F preserves the right homology of a short complex S, this is the
canonical isomorphism (S.map F).rightHomology ≅ F.obj S.rightHomology.
Equations
- S.mapRightHomologyIso F = (S.rightHomologyData.map F).rightHomologyIso
Instances For
When a functor F preserves the left homology of a short complex S, this is the
canonical isomorphism (S.map F).homology ≅ F.obj S.homology.
Equations
- S.mapHomologyIso F = (S.homologyData.left.map F).homologyIso
Instances For
When a functor F preserves the right homology of a short complex S, this is the
canonical isomorphism (S.map F).homology ≅ F.obj S.homology.
Equations
- S.mapHomologyIso' F = (S.homologyData.right.map F).homologyIso ≪≫ F.mapIso S.homologyData.right.homologyIso.symm
Instances For
Given a natural transformation τ : F ⟶ G between functors C ⥤ D which preserve
the left homology of a short complex S, and a left homology data for S,
this is the left homology map data for the morphism S.mapNatTrans τ
obtained by evaluating τ.
Equations
Instances For
Given a natural transformation τ : F ⟶ G between functors C ⥤ D which preserve
the right homology of a short complex S, and a right homology data for S,
this is the right homology map data for the morphism S.mapNatTrans τ
obtained by evaluating τ.
Equations
Instances For
Given a natural transformation τ : F ⟶ G between functors C ⥤ D which preserve
the homology of a short complex S, and a homology data for S,
this is the homology map data for the morphism S.mapNatTrans τ
obtained by evaluating τ.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The natural isomorphism
F.mapShortComplex ⋙ cyclesFunctor D ≅ cyclesFunctor C ⋙ F
for a functor F : C ⥤ D which preserves homology.
Equations
Instances For
The natural isomorphism
F.mapShortComplex ⋙ leftHomologyFunctor D ≅ leftHomologyFunctor C ⋙ F
for a functor F : C ⥤ D which preserves homology.
Equations
Instances For
The natural isomorphism
F.mapShortComplex ⋙ opcyclesFunctor D ≅ opcyclesFunctor C ⋙ F
for a functor F : C ⥤ D which preserves homology.
Equations
Instances For
The natural isomorphism
F.mapShortComplex ⋙ rightHomologyFunctor D ≅ rightHomologyFunctor C ⋙ F
for a functor F : C ⥤ D which preserves homology.
Equations
Instances For
The natural isomorphism
F.mapShortComplex ⋙ homologyFunctor D ≅ homologyFunctor C ⋙ F
for a functor F : C ⥤ D which preserves homology.
Equations
Instances For
If a short complex S is such that S.f = 0 and that the kernel of S.g is preserved
by a functor F, then F preserves the left homology of S.
If a short complex S is such that S.g = 0 and that the cokernel of S.f is preserved
by a functor F, then F preserves the right homology of S.
If a short complex S is such that S.g = 0 and that the cokernel of S.f is preserved
by a functor F, then F preserves the left homology of S.
If a short complex S is such that S.f = 0 and that the kernel of S.g is preserved
by a functor F, then F preserves the right homology of S.