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
Given f, g
with f ≫ g = 0
, the homology of g.op, f.op
is the opposite of the homology of
f, g
.
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Instances For
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
.
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Instances For
Sends a complex X
with objects in V
to the corresponding complex with objects in Vᵒᵖ
.
Equations
- HomologicalComplex.op X = HomologicalComplex.mk (fun (i : ι) => Opposite.op (X.X i)) fun (i j : ι) => (X.d j i).op
Instances For
Sends a complex X
with objects in V
to the corresponding complex with objects in Vᵒᵖ
.
Equations
- HomologicalComplex.opSymm X = HomologicalComplex.mk (fun (i : ι) => Opposite.op (X.X i)) fun (i j : ι) => (X.d j i).op
Instances For
Sends a complex X
with objects in Vᵒᵖ
to the corresponding complex with objects in V
.
Equations
- HomologicalComplex.unop X = HomologicalComplex.mk (fun (i : ι) => (X.X i).unop) fun (i j : ι) => (X.d j i).unop
Instances For
Sends a complex X
with objects in Vᵒᵖ
to the corresponding complex with objects in V
.
Equations
- HomologicalComplex.unopSymm X = HomologicalComplex.mk (fun (i : ι) => (X.X i).unop) fun (i j : ι) => (X.d j i).unop
Instances For
Auxiliary definition for opEquivalence
.
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Auxiliary definition for opEquivalence
.
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Auxiliary definition for opEquivalence
.
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Auxiliary definition for opEquivalence
.
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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
.
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Auxiliary definition for unopEquivalence
.
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Auxiliary definition for unopEquivalence
.
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Auxiliary definition for unopEquivalence
.
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Auxiliary definition for unopEquivalence
.
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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
.
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If K
is a homological complex, then the homology of K.op
identifies to
the opposite of the homology of K
.
Equations
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
Instances For
Auxiliary tautological definition for homologyOp
.
Equations
Instances For
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
.
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Instances For
Auxiliary tautological definition for homologyUnop
.
Equations
Instances For
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
.
Equations
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