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arXiv · 2405.03315

The period-index conjecture for abelian threefolds and Donaldson-Thomas theory

James Hotchkiss·Alexander Perry
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Abstract

We prove the period-index conjecture for unramified Brauer classes on abelian threefolds. To do so, we develop a theory of reduced Donaldson-Thomas invariants for 3-dimensional Calabi-Yau categories, with the feature that the noncommutative variational integral Hodge conjecture holds for classes with nonvanishing invariant. The period-index result is then proved by interpreting it as the algebraicity of a Hodge class on the twisted derived category, and specializing within the Hodge locus to an untwisted abelian threefold with nonvanishing invariant. As a consequence, we also deduce the integral Hodge conjecture for generically twisted abelian threefolds.

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James Hotchkiss, Alexander Perry. 2024-05-06. The period-index conjecture for abelian threefolds and Donaldson-Thomas theory. https://arxiv.org/abs/2405.03315

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