English

Lexsegment ideals and their h-polynomials

Commutative Algebra 2018-07-16 v2

Abstract

Let S=K[x1,,xn]S = K[x_1, \ldots, x_n] denote the polynomial ring in nn variables over a field KK with each deg xi=1\mathrm{deg}\ x_i = 1 and ISI \subset S a homogeneous ideal of SS with dimS/I=d\dim S/I = d. The Hilbert series of S/IS/I is of the form hS/I(λ)/(1λ)dh_{S/I}(\lambda)/(1 - \lambda)^d, where hS/I(λ)=h0+h1λ+h2λ2++hsλsh_{S/I}(\lambda) = h_0 + h_1\lambda + h_2\lambda^2 + \cdots + h_s\lambda^s with hs0h_s \neq 0 is the hh-polynomial of S/IS/I. Given arbitrary integers r1r \geq 1 and s1s \geq 1, a lexsegment ideal II of S=K[x1,,xn]S = K[x_1, \ldots, x_n], where nmax{r,s}+2n \leq \max\{r, s\} + 2, satisfying reg(S/I)=r\mathrm{reg}(S/I) = r and deg hS/I(λ)=s \mathrm{deg}\ h_{S/I}(\lambda) = s will be constructed.

Keywords

Cite

@article{arxiv.1807.02834,
  title  = {Lexsegment ideals and their h-polynomials},
  author = {Takayuki Hibi and Kazunori Matsuda},
  journal= {arXiv preprint arXiv:1807.02834},
  year   = {2018}
}

Comments

4 pages

R2 v1 2026-06-23T02:54:04.151Z