Reconstruction of $g=1$ permutation equivariant quantum $K$-invariants
Dun Tang
TL;DR
The paper proves a genus-1 reconstruction theorem for permutation-equivariant quantum K-theory on general Kähler targets, extending prior work for point targets to arbitrary targets. It uses the permutation-equivariant Ancestor-Descendant correspondence, an $\mathcal{S}$-operator framework, and a residue calculus to separate base-curve and map contributions and to express the genus-1 potential as a combination of a no-descendant part and explicit permuted-cycle contributions. The core result provides a residue-based formula for $\mathcal{F}_1(\mathbf{t})$ in terms of genus-0 data and restricted genus-1 data, including explicit contributions from cycle types $M\in\{2,3,4,6\}$ and an algorithm to compute the descendant inputs $\tau$. The methods unify and generalize Tang1 and Tang2, enabling practical computation of $g=1$ perm-equivariant quantum K-invariants for broad target spaces and highlighting a Dijkgraaf-Witten–style reconstruction phenomenon in this setting.
Abstract
In this paper, we establish an analog of Dijkgraaf-Witten's theorem for $g=1$ invariants in permutation-equivariant quantum K-theory. This result generalizes the findings of \cite{Tang1} and \cite{Tang2}.
