English

On binomial edge ideals of corona of graphs

Commutative Algebra 2025-03-18 v1 Combinatorics

Abstract

For a simple graph GG, let JGJ_G denote the corresponding binomial edge ideal. This article considers the binomial edge ideal of the corona product of two connected graphs GG and HH. The corona product of GG and HH, denoted by GHG\circ H, is a construction where each vertex of GG is connected (via the coning-off) to an entire copy of HH. This is a direct generalization of a cone construction. Previous studies have shown that for JGHJ_{G \circ H} to be Cohen-Macaulay, both GG and HH must be complete graphs. However, there are no general formulae for the dimension, depth, or Castelnuovo-Mumford regularity of JGHJ_{G\circ H} for all graphs GG and HH. In this article, we provide a general formula for the dimension, depth and Castelnuovo-Mumford regularity of the binomial edge ideals of certain corona and corona-type (somewhat a generalization of corona) products of special interests. Additionally, we study the Cohen-Macaulayness, unmixedness and related properties of binomial edge ideals corresponding to above class of graphs. We have also added a short note on the reduction of the Bolognini-Macchia-Strazzanti Conjecture to all graphs with a diameter of 33.

Keywords

Cite

@article{arxiv.2503.12114,
  title  = {On binomial edge ideals of corona of graphs},
  author = {Buddhadev Hajra and Rajib Sarkar},
  journal= {arXiv preprint arXiv:2503.12114},
  year   = {2025}
}

Comments

22 pages, comments and suggestions are welcome