Shapes of spectral sequences obtained from a spectral object #
This file prepares for the construction of the spectral sequence
of a spectral object in an abelian category which shall be conducted
in the file Mathlib/Algebra/Homology/SpectralObject/SpectralSequence.lean (TODO).
In this file, we introduce a structure SpectralSequenceDataCore which
contains a recipe for the construction of the pages of the spectral sequence.
For example, from a spectral object X indexed by EInt the definition
coreE₂Cohomological will allow to construct an E₂ cohomological
spectral sequence such that the object on position (p, q) on the rth
page is E^{p + q}(q - r + 2 ≤ q ≤ q + 1 ≤ q + r - 1).
The data (and properties) in the structure SpectralSequenceDataCore allow
to define the pages and the differentials directly from the SpectralObject
API from the files
Mathlib/Algebra/Homology/SpectralObject/Page.lean and
Mathlib/Algebra/Homology/SpectralObject/Differentials.lean.
However, the computation of the homology of the differentials in
Mathlib/Algebra/Homology/SpectralObject/Homology.lean may not directly
apply: we introduce a typeclass HasSpectralSequence which puts
additional conditions on the spectral object so that the homology of a
page identifies to the next page. These conditions are automatically
satisfied for coreE₂Cohomological, but this design allows
to obtain a spectral sequence with objects of the pages indexed
by ℕ × ℕ instead of ℤ × ℤ when suitable conditions are satisfied by
a spectral object indexed by EInt (see coreE₂CohomologicalNat
and the typeclass IsFirstQuadrant).
This data is a recipe in order to produce a spectral sequence starting on
page r₀ (where the rth page is of shape c r) from a spectral object
indexed by ι. The object on page r at the position pq : κ shall be
E^(deg pq)(i₀ ≤ i₁ ≤ i₂ ≤ i₃), where i₀ ≤ i₁ ≤ i₂ ≤ i₃ are elements in the
index type ι of the spectral object and deg pq : ℤ is a cohomological degree.
The indices i₀ and i₃ depend on r and pq, but i₁, i₂ only depend on pq.
Various conditions are added in order to construct the differentials on the pages
and show that the homology of a page identifies to the next page; in certain
cases, additional conditions may be required on the spectral object.
- deg : κ → ℤ
The cohomological degree of objects in the pages
The zeroth index
- i₁ (pq : κ) : ι
The first index
- i₂ (pq : κ) : ι
The second index
The third index
Instances For
The data which allows to construct an E₂-cohomological spectral sequence
indexed by ℤ × ℤ from a spectral object indexed by EInt.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The data which allows to construct an E₂-cohomological spectral sequence
indexed by ℕ × ℕ from a spectral object indexed by EInt. (Note: additional
assumptions on the spectral object are required for the construction of
the spectral sequence from this.)
Equations
- One or more equations did not get rendered due to their size.
Instances For
The data which allows to construct an E₂-cohomological spectral sequence
indexed by ℤ × Fin l from a spectral object indexed by Fin (l + 1).
Equations
- One or more equations did not get rendered due to their size.
Instances For
The data which allows to construct an E₂-homological spectral sequence
indexed by ℕ × ℕ from a spectral object indexed by EInt. (Note: additional
assumptions on the spectral object are required for the construction of
the spectral sequence from this.)
Equations
- One or more equations did not get rendered due to their size.
Instances For
Given X : SpectralObject C ι and data : SpectralSequenceDataCore ι c r₀, this is
the property which allows to construct a spectral sequence by using the recipe given
by data. The conditions given allow to show that the homology of a page identifies
to the next page.