ScalingStacks

7.4.11. Bordered Heegaard Floer algebras

We consider a chord diagram (𝒵,𝐚)({\mathcal{Z}},{\mathbf{a}}) as in §7.2.4. Let Z1,…,ZlZ_{1},\ldots,Z_{l} be the connected components of 𝒵{\mathcal{Z}}. Let 𝐚~=⋃{z,z′}∈𝐚{z,z′}\tilde{{\mathbf{a}}}=\bigcup_{\{z,z^{\prime}\}\in{\mathbf{a}}}\{z,z^{\prime}\}, ni=|𝐚~∩Zi|n_{i}=|\tilde{{\mathbf{a}}}\cap Z_{i}| and let q:Z~→Zq:\tilde{Z}\to Z be the quotient map.

The isomorphism (7.4.5) associated with the decomposition Z~=Z̊1∐⋯∐Z̊l\tilde{Z}=\mathring{Z}_{1}\coprod\cdots\coprod\mathring{Z}_{l} together with the strands algebra description of §6.3.2 and the isomorphism of Proposition 7.4.33 induce an isomorphism of differential algebras

𝒜(n1)⊗⋯⊗𝒜(nl)→∼Endadd⁡(𝒮⁡(Z~))(⨁I⊂𝐚~I).{\mathcal{A}}(n_{1})\otimes\cdots\otimes{\mathcal{A}}(n_{l})\mathrel{\mathop{\kern 0.0pt\to}\limits^{\sim}}\operatorname{End}\nolimits_{\operatorname{add}\nolimits({\mathcal{S}}(\tilde{Z}))}(\bigoplus_{I\subset\tilde{{\mathbf{a}}}}I).

It is compatible with the gradings, via the embedding G′(n1)×⋯×G′(nl)↪Γ𝐚(Z~)G^{\prime}(n_{1})\times\cdots\times G^{\prime}(n_{l})\hookrightarrow\Gamma_{{\mathbf{a}}}(\tilde{Z}) given by §6.3.2 and §7.4.8.

The differential algebra 𝒜⁡(𝒵){\mathcal{A}}({\mathcal{Z}}) associated to 𝒵{\mathcal{Z}} is a differential (G′(n1)×⋯×G′(nl))(G^{\prime}(n_{1})\times\cdots\times G^{\prime}(n_{l}))-graded non-unital subalgebra of 𝒜(n1)⊗⋯⊗𝒜(nl){\mathcal{A}}(n_{1})\otimes\cdots\otimes{\mathcal{A}}(n_{l}) (cf [Za, Definition 2.6] and [LiOzTh1, Definition 3.23] for the original setting where l=1l=1). There is a unique isomorphism of differential algebras

𝒜⁡(𝒵)→∼Endadd⁡(𝒮⁡(Z))⁡(⨁S⊂𝐚S){\mathcal{A}}({\mathcal{Z}})\mathrel{\mathop{\kern 0.0pt\to}\limits^{\sim}}\operatorname{End}\nolimits_{\operatorname{add}\nolimits({\mathcal{S}}(Z))}\bigl(\bigoplus_{S\subset{\mathbf{a}}}S\bigr)

making the following diagram commutative

𝒜⁡(𝒵)\textstyle{{\mathcal{A}}({\mathcal{Z}})\ignorespaces\ignorespaces\ignorespaces\ignorespaces\ignorespaces\ignorespaces\ignorespaces\ignorespaces}∼\scriptstyle{\sim}Endadd⁡(𝒮⁡(Z))⁡(⨁S⊂𝐚S)\textstyle{\operatorname{End}\nolimits_{\operatorname{add}\nolimits({\mathcal{S}}(Z))}\bigl(\bigoplus_{S\subset{\mathbf{a}}}S\bigr)\ignorespaces\ignorespaces\ignorespaces\ignorespaces}q#\scriptstyle{q^{\#}}𝒜(n1)⊗⋯⊗𝒜(nl)\textstyle{{\mathcal{A}}(n_{1})\otimes\cdots\otimes{\mathcal{A}}(n_{l})\ignorespaces\ignorespaces\ignorespaces\ignorespaces}∼\scriptstyle{\sim}Endadd⁡(𝒮⁡(Z~))⁡(⨁I⊂𝐚~I)\textstyle{\operatorname{End}\nolimits_{\operatorname{add}\nolimits({\mathcal{S}}(\tilde{Z}))}(\bigoplus_{I\subset\tilde{{\mathbf{a}}}}I)}

Original mathematics by the credited authors. Source collection and HTML conversion remain in progress.

Andrew Manion, Raphael Rouquier

Original source: arXiv:2009.09627v2