English

Homological shifts of powers a complementary edge ideal

Commutative Algebra 2026-01-27 v5

Abstract

The homological shift algebra and the projective dimension function of complementary edge ideals are investigated. Let GG be a connected graph, and let II be its complementary edge ideal. For bipartite graphs GG, we show that the projective dimension of IsI^s increases strictly with ss until reaching its maximum value. For trees and cycles, explicit expressions for the projective dimension of IsI^s are provided, along with detailed descriptions of their homological shift algebras. In particular, it is shown that the ii-th homological shift algebra of such ideals is generated in degree at most ii. Additionally, we prove that if GG is a tree, then the homological shift ideal HSi(Ii)\mathrm{HS}_i(I^i), when divided by a suitable monomial, becomes a Veronese-type ideal, and every Veronese-type ideal arises in this manner.

Keywords

Cite

@article{arxiv.2511.13267,
  title  = {Homological shifts of powers a complementary edge ideal},
  author = {Dancheng Lu and Zexin Wang and Guangjun Zhu},
  journal= {arXiv preprint arXiv:2511.13267},
  year   = {2026}
}

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