English

Calabi-Yau structures on derived and singularity categories of symmetric orders

Representation Theory 2026-02-03 v2 Algebraic Geometry Category Theory K-Theory and Homology

Abstract

We construct left and right Calabi-Yau structures on derived respectively singularity categories of symmetric orders Λ\Lambda over commutative Gorenstein rings RR. For this, we first construct Calabi-Yau structures over RR by lifting Amiot's construction of Calabi-Yau structures on Verdier quotients to the dg level. Then we prove base change properties relating Calabi-Yau structures over RR to those over the base field kk. As a result, we prove the existence of a right Calabi-Yau structure on the dg singularity category associated with Λ\Lambda which is a cyclic lift of the weak Calabi-Yau structure constructed by the first-named author and Iyama. We also show the existence of a left Calabi-Yau structure on the dg bounded derived category of Λ\Lambda. This is a non-commutative generalization of a result by Brav and Dyckerhoff. By combining the existence of the right Calabi-Yau structure on the dg singularity category with a structure theorem by Keller and the second-named author, we deduce that under suitable hypotheses, the singularity category associated with Λ\Lambda is triangle equivalent to a generalized cluster category in the sense of Amiot.

Keywords

Cite

@article{arxiv.2512.03836,
  title  = {Calabi-Yau structures on derived and singularity categories of symmetric orders},
  author = {Norihiro Hanihara and Junyang Liu},
  journal= {arXiv preprint arXiv:2512.03836},
  year   = {2026}
}

Comments

20 pages; v2: Theorem A extended to the Hochschild homology with coefficients setting (similar proof)