English

Graded Betti numbers of some circulant graphs

Combinatorics 2025-10-06 v1

Abstract

Let GG be the circulant graph Cn(S)C_n(S) with S{1,2,,n2}S \subseteq \{1, 2, \dots, \lfloor \frac{n}{2} \rfloor\}, and let I(G)I(G) denote the edge ideal in the polynomial ring R=K[x0,x1,,xn1]R=\mathbb{K}[x_0, x_1, \dots, x_{n-1}] over a field K\mathbb{K}. In this paper, we compute the N\mathbb{N}-graded Betti numbers of the edge ideals of three families of circulant graphs Cn(1,2,,j^,,n2)C_n(1,2,\dots,\widehat{j},\dots,\lfloor \frac{n}{2} \rfloor), Clm(1,2,,2l^,,3l^,,lm2)C_{lm}(1,2,\dots,\widehat{2l},\dots, \widehat{3l},\dots,\lfloor \frac{lm}{2} \rfloor) and Clm(1,2,,l^,,2l^,,3l^,,lm2)C_{lm}(1,2,\dots,\widehat{l},\dots,\widehat{2l},\dots, \widehat{3l},\dots,\lfloor \frac{lm}{2} \rfloor). Other algebraic and combinatorial properties like regularity, projective dimension, induced matching number and when such graphs are well-covered, Cohen-Macaulay, Sequentially Cohen-Macaulay, Buchsbaum and S2S_2 are also discussed.

Keywords

Cite

@article{arxiv.2007.02401,
  title  = {Graded Betti numbers of some circulant graphs},
  author = {Sonica Anand and Amit Roy},
  journal= {arXiv preprint arXiv:2007.02401},
  year   = {2025}
}

Comments

20 pages, 3 figures

R2 v1 2026-06-23T16:52:02.309Z