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arXiv · 2608.15460

Support $\tau$-tilting posets and Hochschild reconstruction for matrix centralizer algebras

Jiangsheng Hu·Yu-Zhe Liu·Tiwei Zhao
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Abstract

Let $R$ be a field and $A$ the endomorphism algebra of a finite direct sum of cyclic modules over a finite-dimensional commutative local principal ideal $R$-algebra. We construct a central quotient showing that the support $\tau$-tilting poset of $A$ is isomorphic to the poset of the symmetric group with the weak order. We show that the center of $A$ and degree-zero Hochschild homology, viewed as a module over the center, determine the truncated local algebra and the multiset of successive length gaps. For centralizer matrix algebras, the support $\tau$-tilting poset determines the multiset of distinct-exponent counts of the primary blocks. The corresponding algebra--module pair also recovers their local algebras and gap multisets. Combining this reconstruction with the known derived equivalence classification, we characterize derived equivalence by isomorphism of these algebra-module pairs. We apply the results to Morita reconstruction in the string and gentle classes.

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Jiangsheng Hu, Yu-Zhe Liu, Tiwei Zhao. 2026-08-16. Support $\tau$-tilting posets and Hochschild reconstruction for matrix centralizer algebras. https://arxiv.org/abs/2608.15460

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