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Intrinsic Donaldson-Thomas theory. II. Stability measures and invariants

Chenjing Bu, Andrés Ibáñez Núñez, Tasuki Kinjo

TL;DR

This work extends intrinsic Donaldson–Thomas theory to general $(-1)$-shifted symplectic stacks by introducing stability measures on the component lattice and constructing epsilon motives as motivic enumerative invariants. It develops a comprehensive motivic framework based on rings of motives, Hall induction, and a Möbius-convolution perspective, culminating in numeric and motivic DT invariants $\mathrm{DT}_\mathcal{X}^{(k)}(\mu)$ and $\mathrm{DT}_\mathcal{X}^{(k),\mathrm{mot}}(\mu)$ defined via $\epsilon_\mathcal{X}^{(k)}(\mu)$ and Behrend-type weightings. A central technical achievement is the no-pole theorem, ensuring the invariants are well-defined after suitable rescaling by powers of $(\mathbb{L}-1)$, with a detailed treatment of Theta-stratifications and their interaction with stability data. The paper lays a robust, intrinsic foundation for wall-crossing and further enumerative structures, with planned applications towall-crossing and multiple-cover phenomena in Part III.

Abstract

This is the second paper in a series on intrinsic Donaldson-Thomas theory, a framework for studying the enumerative geometry of general algebraic stacks. In this paper, we present the construction of Donaldson-Thomas invariants for general $(-1)$-shifted symplectic derived Artin stacks, generalizing the constructions of Joyce-Song and Kontsevich-Soibelman for moduli stacks of objects in $3$-Calabi-Yau abelian categories. Our invariants are defined using rings of motives, and depend intrinsically on the stack, together with a set of combinatorial data similar to a stability condition, called a stability measure on the component lattice of the stack. For our invariants to be well-defined, we prove a generalization of Joyce's no-pole theorem to general stacks, using a simpler and more conceptual argument than the original proof in the abelian category case. Further properties and applications of these invariants, such as wall-crossing formulae, will be discussed in a forthcoming paper.

Intrinsic Donaldson-Thomas theory. II. Stability measures and invariants

TL;DR

This work extends intrinsic Donaldson–Thomas theory to general -shifted symplectic stacks by introducing stability measures on the component lattice and constructing epsilon motives as motivic enumerative invariants. It develops a comprehensive motivic framework based on rings of motives, Hall induction, and a Möbius-convolution perspective, culminating in numeric and motivic DT invariants and defined via and Behrend-type weightings. A central technical achievement is the no-pole theorem, ensuring the invariants are well-defined after suitable rescaling by powers of , with a detailed treatment of Theta-stratifications and their interaction with stability data. The paper lays a robust, intrinsic foundation for wall-crossing and further enumerative structures, with planned applications towall-crossing and multiple-cover phenomena in Part III.

Abstract

This is the second paper in a series on intrinsic Donaldson-Thomas theory, a framework for studying the enumerative geometry of general algebraic stacks. In this paper, we present the construction of Donaldson-Thomas invariants for general -shifted symplectic derived Artin stacks, generalizing the constructions of Joyce-Song and Kontsevich-Soibelman for moduli stacks of objects in -Calabi-Yau abelian categories. Our invariants are defined using rings of motives, and depend intrinsically on the stack, together with a set of combinatorial data similar to a stability condition, called a stability measure on the component lattice of the stack. For our invariants to be well-defined, we prove a generalization of Joyce's no-pole theorem to general stacks, using a simpler and more conceptual argument than the original proof in the abelian category case. Further properties and applications of these invariants, such as wall-crossing formulae, will be discussed in a forthcoming paper.

Paper Structure

This paper contains 24 sections, 12 theorems, 128 equations, 2 figures.

Key Result

Lemma 5.1.5

The operators $\pi_\mathcal{X}^{(k)}$ are uniquely defined by the properties in para-def-virtual-rank. Moreover, in the integral eq-def-pi-k, we may replace $\mathsf{Face}^\mathrm{sp} (\mathcal{Z})$ by any larger finite full subcategory $\mathcal{F} \subset \mathsf{Face}^\mathrm{nd} (\mathcal{Z})$,

Figures (2)

  • Figure 1: The component lattice of $\mathcal{X}_\gamma$
  • Figure 2: Component lattices for the two quivers

Theorems & Definitions (22)

  • Example 3.4.2: Linear moduli stacks
  • Example 4.1.5: Trivial measure
  • Example 4.1.6: Canonical measure
  • Example 4.1.7: Linear moduli stacks
  • Example 5.1.2: Linear moduli stacks
  • Lemma 5.1.5
  • Theorem 5.1.7
  • Theorem 5.1.8
  • Lemma 5.2.5
  • Example 5.2.6: Virtual rank projections
  • ...and 12 more