English

Cohen-Macaulay Binomial edge ideals in terms of blocks with whiskers

Commutative Algebra 2022-03-10 v1

Abstract

For a graph GG, Bolognini et al. have shown JGJ_{G} is strongly unmixed \Rightarrow JGJ_{G} is Cohen-Macaulay \Rightarrow GG is accessible, where JGJ_{G} denotes the binomial edge ideals of GG. Accessible and strongly unmixed properties are purely combinatorial. We give some motivations to focus only on blocks with whiskers for the characterization of all GG with Cohen-Macaulay JGJ_{G}. We show that accessible and strongly unmixed properties of GG depend only on the corresponding properties of its blocks with whiskers and vice versa. Also, we give an infinite class of graphs whose binomial edge ideals are Cohen-Macaulay, and from that, we classify all rr-regular rr-connected graphs such that attaching some special whiskers to it, the binomial edge ideals become Cohen-Macaulay. Finally, we define a new class of graphs, called \textit{strongly rr-cut-connected} and prove that the binomial edge ideal of any strongly rr-cut-connected accessible graph having at most three cut vertices is Cohen-Macaulay.

Keywords

Cite

@article{arxiv.2203.04652,
  title  = {Cohen-Macaulay Binomial edge ideals in terms of blocks with whiskers},
  author = {Kamalesh Saha and Indranath Sengupta},
  journal= {arXiv preprint arXiv:2203.04652},
  year   = {2022}
}