Homotopy commutative square of converging spectral sequences #
A homotopy commutative square of converging spectral sequences:
V₁ --f--> V₂
|p |q
v v
V₃ --g--> V₄
Together with ESS data for each morphism and a commutativity condition
expressing that q ∘ f = g ∘ p at the abutment level.
- cmf : ConvergenceMorphism conv₁ conv₂
Top morphism: V₁ → V₂
- cmp : ConvergenceMorphism conv₁ conv₃
Left morphism: V₁ → V₃
- cmq : ConvergenceMorphism conv₂ conv₄
Right morphism: V₂ → V₄
- cmg : ConvergenceMorphism conv₃ conv₄
Bottom morphism: V₃ → V₄
- essf : ExtensionSS self.cmf
ESS data for the top morphism f
- essp : ExtensionSS self.cmp
ESS data for the left morphism p
- essq : ExtensionSS self.cmq
ESS data for the right morphism q
- essg : ExtensionSS self.cmg
ESS data for the bottom morphism g
- abutment_comm (k' : ω') : CategoryTheory.CategoryStruct.comp (self.cmf.aMap k') (self.cmq.aMap k') = CategoryTheory.CategoryStruct.comp (self.cmp.aMap k') (self.cmg.aMap k')
Commutativity at the abutment level: q ∘ f = g ∘ p on target objects
- eInfty_comm (k : ω) : CategoryTheory.CategoryStruct.comp (self.cmf.eMap k) (self.cmq.eMap k) = CategoryTheory.CategoryStruct.comp (self.cmp.eMap k) (self.cmg.eMap k)
Commutativity at the E∞-page level: q ∘ f = g ∘ p on E∞ classes
Instances For
ESS differential relation predicate #
The ESS differential d_n sends the class at bidegree k₁ to the class
at bidegree k₂: expressed as the ESS differential object being nontrivial
and witnessing the relation. This is a Prop-level predicate abstracting the
ESS differential relation from Proposition 2.5.
Equations
- KIP.SpectralSequence.ESSRelation ess n k₁ k₂ = ¬CategoryTheory.Limits.IsZero (ess.essDiff n k₁ k₂)
Instances For
The ESS differential d_n sends the class at k₁ to zero at k₂.
Equations
- KIP.SpectralSequence.ESSVanishes ess n k₁ k₂ = CategoryTheory.Limits.IsZero (ess.essDiff n k₁ k₂)
Instances For
No-crossing condition for an ESS differential datum, bundled with the convergence data. Takes the differential datum as a parameter (following Extension.lean patterns).
Equations
Instances For
No-crossing-range condition for an ESS differential datum.
Equations
Instances For
Theorem 2.12 — Commutativity (main theorem) #
Theorem 2.12: Commutativity of ESS differentials (full version).
Given a homotopy commutative square and:
d_n^f(x) = y(ESS differential of f)d_m^p(x) = z(ESS differential of p)- One of (1) or (2) has no crossing
d_l^g(z) = wwith no crossing hitting Fil ≥ s + n + k (for 0 < k ≤ m + l − n)d_{k-1}^q(y) = 0with no crossing
Then d_{m+l-n}^q(y) = w.
Theorem 2.12 (value form): The ESS differential d_{m+l-n}^q(y) equals
the composition of d_l^g(z) through the commutativity square, expressed
as an isomorphism between the differential objects.
Corollary 2.15 — Simplified commutativity (no crossing everywhere) #
Corollary 2.15: Simplified commutativity — same as Thm 2.12 but with
d_l^g(z) = w having no crossing at all (dropping the k parameter).
Corollary 2.15 (iso form): Under no-crossing-everywhere, the differential objects are isomorphic.
Corollary 2.16 — Triangle case #
Corollary 2.16 (Triangle): When V₃ = V₄ and g = id.
V₁ --f--> V₂
\ |q
p\ v
\--> V₃
If d_n^f(x) = y and d_m^p(x) = z with no crossing on one of them,
then d_{m-n}^q(y) = z.
Corollary 2.16 (iso form): Triangle case iso.
Corollary 2.17 — Composition case #
Corollary 2.17 (Composition): When V₁ = V₂ and f = id.
V₁ --p--> V₃
\ |g
q\ v
\--> V₄
If d_m^p(x) = z and d_l^g(z) = w with no crossing on g, then
d_{m+l}^q(x) = w.
Corollary 2.17 (iso form): Composition case iso.
Corollary 2.18 — Induced map on ESS pages #
The ESS page map induced by the commutativity square: if the source E∞-pages
have E₀ = E_r (degeneration at page r), then the commutativity data
induces a well-defined map between the f-ESS and g-ESS pages.
Corollary 2.18 (compatibility): The induced page map commutes with ESS differentials.
Corollary 2.19 — Null composition #
Corollary 2.19: If g ∘ f is null-homotopic and d_n^f(x) = y,
then y is a permanent cycle in the g-ESS: d_m^g(y) = 0 for all m ≥ 0.
Supporting axioms — Commutativity functoriality #
Commutativity squares preserve boundary groups: the boundary in the q-ESS
at page m + l - n is related to the boundary in the g-ESS at page l.
The HomotopyCommSquare is natural in the following sense: the induced maps on ESS differentials respect composition of convergence morphisms.
The commutativity data is compatible with the E∞ page maps.
The filtration data is compatible across the commutativity square.
Triangle and composition reductions #
Triangle reduction: Corollary 2.16 specializes from the full commutativity.
Composition reduction: Corollary 2.17 specializes from the full commutativity.
Boundary transfer #
Boundary transfer under the commutativity square: an element in the ESS boundary of the q-differential maps to an element in the ESS boundary of the g-differential under appropriate conditions.
ESS page functoriality under commutativity #
The ESS page at level n is functorial: the page map induced by the commutativity square respects composition of convergence morphisms at each ESS page.
The detection set data is compatible with the commutativity square maps.
Commutativity is preserved under ESS page transition: if the commutativity relation holds at page n, it holds at page n+1 (assuming no new crossings).