English

Fano and weak Fano Hessenberg varieties

Algebraic Geometry 2020-03-30 v1 Combinatorics Representation Theory

Abstract

Regular semisimple Hessenberg varieties are smooth subvarieties of the flag variety, and their examples contain the flag variety itself and the permutohedral variety which is a toric variety. We give a complete classification of Fano and weak Fano regular semisimple Hessenberg varieties in type A in terms of combinatorics of Hessenberg functions. In particular, we show that if the anti-canonical bundle of a regular semisimple Hessenberg variety is nef, then it is in fact nef and big.

Keywords

Cite

@article{arxiv.2003.12286,
  title  = {Fano and weak Fano Hessenberg varieties},
  author = {Hiraku Abe and Naoki Fujita and Haozhi Zeng},
  journal= {arXiv preprint arXiv:2003.12286},
  year   = {2020}
}

Comments

42 pages, 14 figures

R2 v1 2026-06-23T14:29:00.459Z