Betti Tate's thesis and the trace of perverse schobers
Benjamin Gammage, Justin Hilburn
TL;DR
The paper formulates and proves a Betti-analytic analogue of Tate's thesis, identifying the categorical trace of the 2-category of perverse schobers with an automorphic-to-spectral equivalence on Betti loop spaces. By combining a Betti geometric class field theory, a 3d mirror symmetry framework, and a spectral-trace result of Ben-Zvi–Nadler–Preygel, the authors establish the conjectured trace equivalence in the simplest nontrivial case, where the A-model trace of spherical adjunctions matches cosheaves on the Betti loop space. The construction hinges on a detailed analysis of cosheaves on placid ind-schemes, a stratified description of the Betti loop space, and explicit finite-type approximations leading to an equivalence $\mathsf{Sh}^!_\mathcal{S}(\mathfrak{L}\mathbb{C}) \simeq \mathsf{IndCoh}(\mathcal{L}_B(\mathbb{C}/\mathbb{C}^\times))$. This work provides a blueprint for extending trace-like invariants of 2-categories (such as the 2-category of perverse schobers) to loop-space sheaf theories, with implications for 3d- and 4d-topological field theories and holomorphic symplectic geometry.
Abstract
We propose a conjecture on the categorical trace of the 2-category of perverse schobers (expected to model the Fukaya-Fueter 2-category of a holomorphic symplectic space). By proving a Betti geometric version of Tate's thesis, and combining it with our previous 3d mirror symmetry equivalence and the Ben-Zvi--Nadler--Preygel result on spectral traces, we are able to establish our conjecture in the simplest interesting case.
