Connecting a chain complex and a cochain complex #
Given a chain complex K
: ... ⟶ K.X 2 ⟶ K.X 1 ⟶ K.X 0
,
a cochain complex L
: L.X 0 ⟶ L.X 1 ⟶ L.X 2 ⟶ ...
,
a morphism d₀: K.X 0 ⟶ L.X 0
satisfying the identifies K.d 1 0 ≫ d₀ = 0
and d₀ ≫ L.d 0 1 = 0
, we construct a cochain complex indexed by ℤ
of the form
... ⟶ K.X 2 ⟶ K.X 1 ⟶ K.X 0 ⟶ L.X 0 ⟶ L.X 1 ⟶ L.X 2 ⟶ ...
,
where K.X 0
lies in degree -1
and L.X 0
in degree 0
.
Given K : ChainComplex C ℕ
and L : CochainComplex C ℕ
, this data
allows to connect K
and L
in order to get a cochain complex indexed by ℤ
,
see ConnectData.cochainComplex
.
the differential which connect
K
andL
Instances For
Auxiliary definition for ConnectData.cochainComplex
.
Equations
- CochainComplex.ConnectData.X K L (Int.ofNat n) = L.X n
- CochainComplex.ConnectData.X K L (Int.negSucc n) = K.X n
Instances For
Auxiliary definition for ConnectData.cochainComplex
.
Equations
- h.d (Int.ofNat n) (Int.ofNat m) = L.d n m
- h.d (Int.negSucc n) (Int.negSucc m) = K.d n m
- h.d (Int.negSucc 0) (Int.ofNat 0) = h.d₀
- h.d (Int.ofNat a) (Int.negSucc a_1) = 0
- h.d (Int.negSucc a) (Int.ofNat a_1) = 0
Instances For
Given h : ConnectData K L
where K : ChainComplex C ℕ
and L : CochainComplex C ℕ
,
this is the cochain complex indexed by ℤ
obtained by connecting K
and L
:
... ⟶ K.X 2 ⟶ K.X 1 ⟶ K.X 0 ⟶ L.X 0 ⟶ L.X 1 ⟶ L.X 2 ⟶ ...
.
Equations
- h.cochainComplex = { X := CochainComplex.ConnectData.X K L, d := h.d, shape := ⋯, d_comp_d' := ⋯ }