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On the Hochschild cohomology of Tamarkin categories

Christopher Kuo, Vivek Shende, Bingyu Zhang

TL;DR

The paper develops a filtered Hochschild-theoretic framework for Tamarkin categories associated to open subsets of cotangent bundles, proving that the action-filtered Hochschild cohomology of the Tamarkin category 𝒯(U) matches the corresponding filtered symplectic cohomology SH of the neighborhood. It introduces a projector calculus for traces in the Tamarkin setting, expressing traces via integral kernels and wrapping constructs, and relates these to the Guillermou–Viterbo comparison to Floer theory. A Calabi–Yau structure is established for 𝒯(U), tying Hochschild (co)homology to trace data, and the action-window formalism provides a precise link between 𝒯(U) and SH with filtration. The results extend to generating function homology and clarify how capacities defined via SH are recovered in the Tamarkin/sheaf-theoretic framework, offering a robust bridge between microlocal sheaf theory and filtered Floer theory. Overall, the work furnishes a variational, sheaf-theoretic route to filtered symplectic invariants and their algebraic structures, reinforcing connections across Tamarkin, wrapped Fukaya categories, and generating function approaches.

Abstract

To any open subset of a cotangent bundle, Tamarkin has associated a certain quotient of a category of sheaves. Here we show that the Hochschild cohomology of this category agrees with filtered symplectic cohomology.

On the Hochschild cohomology of Tamarkin categories

TL;DR

The paper develops a filtered Hochschild-theoretic framework for Tamarkin categories associated to open subsets of cotangent bundles, proving that the action-filtered Hochschild cohomology of the Tamarkin category 𝒯(U) matches the corresponding filtered symplectic cohomology SH of the neighborhood. It introduces a projector calculus for traces in the Tamarkin setting, expressing traces via integral kernels and wrapping constructs, and relates these to the Guillermou–Viterbo comparison to Floer theory. A Calabi–Yau structure is established for 𝒯(U), tying Hochschild (co)homology to trace data, and the action-window formalism provides a precise link between 𝒯(U) and SH with filtration. The results extend to generating function homology and clarify how capacities defined via SH are recovered in the Tamarkin/sheaf-theoretic framework, offering a robust bridge between microlocal sheaf theory and filtered Floer theory. Overall, the work furnishes a variational, sheaf-theoretic route to filtered symplectic invariants and their algebraic structures, reinforcing connections across Tamarkin, wrapped Fukaya categories, and generating function approaches.

Abstract

To any open subset of a cotangent bundle, Tamarkin has associated a certain quotient of a category of sheaves. Here we show that the Hochschild cohomology of this category agrees with filtered symplectic cohomology.
Paper Structure (29 sections, 73 theorems, 229 equations, 2 figures)

This paper contains 29 sections, 73 theorems, 229 equations, 2 figures.

Key Result

Theorem 1.1

The category $\mathscr{T} (U)$ is linear over $\mathscr{T}$, and $\mathscr{T}$-linearly dualizable. Thus we may take the $\mathscr{T}$-linear trace and in particular have $\operatorname{Tr}(1_{ \mathscr{T} (U)}) \in \mathscr{T}$.

Figures (2)

  • Figure :
  • Figure :

Theorems & Definitions (157)

  • Theorem 1.1: Prop. \ref{['t linear']} and \ref{['t dualizable']}
  • Theorem 1.2
  • Corollary 1.3
  • Definition 2.1
  • Lemma 2.2
  • proof
  • Lemma 2.3
  • proof
  • Lemma 2.4
  • proof
  • ...and 147 more