English

Functorially finite hearts, simple-minded systems in negative cluster categories, and noncrossing partitions

Representation Theory 2021-09-09 v3 Combinatorics

Abstract

Let QQ be an acyclic quiver and w1w \geq 1 be an integer. Let Cw(kQ)\mathsf{C}_{-w} (\mathbf{k} Q) be the (w)(-w)-cluster category of kQ\mathbf{k} Q. We show that there is a bijection between simple-minded collections in Db(kQ)\mathsf{D}^b (\mathbf{k} Q) lying in a fundamental domain of Cw(kQ)\mathsf{C}_{-w} (\mathbf{k} Q) and ww-simple-minded systems in Cw(kQ)\mathsf{C}_{-w} (\mathbf{k} Q). This generalises the same result of Iyama-Jin in the case that QQ is Dynkin. A key step in our proof is the observation that the heart H\mathsf{H} of a bounded t-structure in a Hom-finite, Krull-Schmidt, k\mathbf{k}-linear saturated triangulated category D\mathsf{D} is functorially finite in D\mathsf{D} if and only if H\mathsf{H} has enough injectives and enough projectives. We then establish a bijection between ww-simple-minded systems in Cw(kQ)\mathsf{C}_{-w} (\mathbf{k} Q) and positive ww-noncrossing partitions of the corresponding Weyl group WQW_Q.

Keywords

Cite

@article{arxiv.2004.00604,
  title  = {Functorially finite hearts, simple-minded systems in negative cluster categories, and noncrossing partitions},
  author = {Raquel Coelho Simoes and David Pauksztello and David Ploog with an appendix by Raquel Coelho Simoes and David Pauksztello and Alexandra Zvonareva},
  journal= {arXiv preprint arXiv:2004.00604},
  year   = {2021}
}

Comments

33 pages, to be published in Compositio Mathematica. Many improvements over the previous version due to the reports. Assumptions in Theorem C now include that the category is saturated. The appendix (new in v2) by the first two authors and Alexandra Zvonareva gives an alternative proof for a result by Haibo Jin on the reduction of simple-minded collections