English

Binomial edge ideals of weakly closed graphs

Commutative Algebra 2022-08-30 v2 Combinatorics

Abstract

Closed graphs have been characterized by Herzog et al. as the graphs whose binomial edge ideals have a quadratic Gr\"obner basis with respect to a diagonal term order. In this paper, we focus on a generalization of closed graphs, namely weakly-closed graphs (or co-comparability graphs). Build on some results about Knutson ideals of generic matrices, we characterize weakly closed graphs as the only graphs whose binomial edge ideals are Knutson ideals for a certain polynomial ff. In doing so, we re-prove Matsuda's theorem about the F-purity of binomial edge ideals of weakly closed graphs in positive characteristic and we extend it to generalized binomial edge ideals. Furthermore, we give a characterization of weakly closed graphs in terms of the minimal primes of their binomial edge ideals and we characterize all minimal primes of Knutson ideals for this choice of ff.

Keywords

Cite

@article{arxiv.2208.10749,
  title  = {Binomial edge ideals of weakly closed graphs},
  author = {Lisa Seccia},
  journal= {arXiv preprint arXiv:2208.10749},
  year   = {2022}
}
R2 v1 2026-06-25T01:53:38.070Z