English

The homological shift algebra of a monomial ideal

Commutative Algebra 2025-04-18 v3 Combinatorics

Abstract

Let S=K[x1,,xn]S=K[x_1,\dots,x_n] be the polynomial ring over a field KK, and let ISI\subset S be a monomial ideal. In this paper, we introduce the iith \textit{homological shift algebras} HSi(R(I))=k1HSi(Ik)\text{HS}_i(\mathcal{R}(I))=\bigoplus_{k\ge1}\text{HS}_i(I^k) of II. If II has linear powers, these algebras have the structure of a finitely generated bigraded module over the Rees algebra R(I)\mathcal{R}(I) of II. Hence, many invariants of HSi(Ik)\text{HS}_i(I^k), such as depth, associated primes, regularity, and the v\text{v}-number, exhibit well behaved asymptotic behavior. We determine several families of monomial ideals II for which HSi(Ik)\text{HS}_i(I^k) has linear resolution for all k0k\gg0. Finally, we show that HSi(Ik)\text{HS}_i(I^k) is Golod for all monomial ideals ISI\subset S with linear powers and all k0k\gg0.

Keywords

Cite

@article{arxiv.2412.21031,
  title  = {The homological shift algebra of a monomial ideal},
  author = {Antonino Ficarra and Ayesha Asloob Qureshi},
  journal= {arXiv preprint arXiv:2412.21031},
  year   = {2025}
}

Comments

Dedicated with deep gratitude to the memory of Professor J\"urgen Herzog, inspiring mathematician and master of monomials. Some references fixed