English

Vertex decomposability and weakly polymatroidal ideals

Commutative Algebra 2024-10-30 v2 Combinatorics

Abstract

Let KK be a field and R=K[x1,,xn]R=K[x_1,\ldots, x_n] be the polynomial ring in nn variables over a field KK. Let Δ\Delta be a simplicial complex on nn vertices and I=IΔI=I_{\Delta} be its Stanley-Reisner ideal. In this paper, we show that if II is a matroidal ideal then the following conditions are equivalent: (i)(i) Δ\Delta is sequentially Cohen-Macaulay; (ii)(ii) Δ\Delta is shellable; (iii)(iii) Δ\Delta is vertex decomposable. Also, if II is a minimally generated by u1,,usu_1,\ldots,u_s such that s3s\leq 3 or supp(ui)supp(uj)={x1,,xn}{\rm supp}(u_i)\cup {\rm supp}(u_j)=\{x_1,\ldots,x_n\} for all iji\neq j, then Δ\Delta is vertex decomposable. Furthermore, we prove that if II is a monomial ideal of degree 22 then II is weakly polymatroidal if and only if II has linear quotients if and only if II is vertex splittable.

Keywords

Cite

@article{arxiv.2201.06756,
  title  = {Vertex decomposability and weakly polymatroidal ideals},
  author = {Amir Mafi and Dler Naderi and Hero Saremi},
  journal= {arXiv preprint arXiv:2201.06756},
  year   = {2024}
}

Comments

8 pages, to appear in J. Algebraic Systems

R2 v1 2026-06-24T08:53:09.790Z