Opposite categories of complexes #
Given a preadditive category V
, the opposite of its category of chain complexes is equivalent to
the category of cochain complexes of objects in Vᵒᵖ
. We define this equivalence, and another
analogous equivalence (for a general category of homological complexes with a general
complex shape).
We then show that when V
is abelian, if C
is a homological complex, then the homology of
op(C)
is isomorphic to op
of the homology of C
(and the analogous result for unop
).
Implementation notes #
It is convenient to define both op
and opSymm
; this is because given a complex shape c
,
c.symm.symm
is not defeq to c
.
Tags #
opposite, chain complex, cochain complex, homology, cohomology, homological complex
Sends a complex X
with objects in V
to the corresponding complex with objects in Vᵒᵖ
.
Equations
- X.op = { X := fun (i : ι) => Opposite.op (X.X i), d := fun (i j : ι) => (X.d j i).op, shape := ⋯, d_comp_d' := ⋯ }
Instances For
Sends a complex X
with objects in V
to the corresponding complex with objects in Vᵒᵖ
.
Equations
- X.opSymm = { X := fun (i : ι) => Opposite.op (X.X i), d := fun (i j : ι) => (X.d j i).op, shape := ⋯, d_comp_d' := ⋯ }
Instances For
Sends a complex X
with objects in Vᵒᵖ
to the corresponding complex with objects in V
.
Equations
- X.unop = { X := fun (i : ι) => Opposite.unop (X.X i), d := fun (i j : ι) => (X.d j i).unop, shape := ⋯, d_comp_d' := ⋯ }
Instances For
Sends a complex X
with objects in Vᵒᵖ
to the corresponding complex with objects in V
.
Equations
- X.unopSymm = { X := fun (i : ι) => Opposite.unop (X.X i), d := fun (i j : ι) => (X.d j i).unop, shape := ⋯, d_comp_d' := ⋯ }
Instances For
Auxiliary definition for opEquivalence
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Auxiliary definition for opEquivalence
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Auxiliary definition for opEquivalence
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Auxiliary definition for opEquivalence
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
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
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Auxiliary definition for unopEquivalence
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Auxiliary definition for unopEquivalence
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Auxiliary definition for unopEquivalence
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Auxiliary definition for unopEquivalence
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
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
.
Equations
- One or more equations did not get rendered due to their size.
Instances For
If K
is a homological complex, then the homology of K.op
identifies to
the opposite of the homology of K
.
Equations
- K.homologyOp i = (K.sc i).homologyOpIso
Instances For
If K
is a homological complex in the opposite category,
then the homology of K.unop
identifies to the opposite of the homology of K
.
Equations
- K.homologyUnop i = (K.unop.homologyOp i).unop
Instances For
The canonical isomorphism K.op.cycles i ≅ op (K.opcycles i)
.
Equations
- K.cyclesOpIso i = (K.sc i).cyclesOpIso
Instances For
The canonical isomorphism K.op.opcycles i ≅ op (K.cycles i)
.
Equations
- K.opcyclesOpIso i = (K.sc i).opcyclesOpIso
Instances For
The natural isomorphism K.op.cycles i ≅ op (K.opcycles i)
.
Equations
- HomologicalComplex.cyclesOpNatIso V c i = CategoryTheory.NatIso.ofComponents (fun (K : (HomologicalComplex V c)ᵒᵖ) => (Opposite.unop K).cyclesOpIso i) ⋯
Instances For
The natural isomorphism K.op.opcycles i ≅ op (K.cycles i)
.
Equations
- HomologicalComplex.opcyclesOpNatIso V c i = CategoryTheory.NatIso.ofComponents (fun (K : (HomologicalComplex V c)ᵒᵖ) => (Opposite.unop K).opcyclesOpIso i) ⋯
Instances For
The natural isomorphism K.op.homology i ≅ op (K.homology i)
.
Equations
- HomologicalComplex.homologyOpNatIso V c i = CategoryTheory.NatIso.ofComponents (fun (K : (HomologicalComplex V c)ᵒᵖ) => (Opposite.unop K).homologyOp i) ⋯