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We define nice partitions of the multicomplex associated to a Stanley ideal. As the main result we show that if the monomial ideal $I$ is a CM Stanley ideal, then $I^p$ is a Stanley ideal as well, where $I^p$ is the polarization of $I$.

Combinatorics · Mathematics 2009-11-12 Sarfraz Ahmad

Let $\mathcal{C}$ be a clutter with a perfect matching $e_1,...,e_g$ of K\"onig type and let $\Delta_\mathcal{C}$ be the Stanley-Reisner complex of the edge ideal of $\mathcal{C}$. If all c-minors of $\mathcal{C}$ have a free vertex and…

Commutative Algebra · Mathematics 2011-04-05 Susan Morey , Enrique Reyes , Rafael H. Villarreal

We show that all monomial ideals in the polynomial ring in at most 3 variables are pretty clean and that an arbitrary monomial ideal $I$ is pretty clean if and only if its polarization $I^p$ is clean. This yields a new characterization of…

Commutative Algebra · Mathematics 2007-05-23 Ali Soleyman Jahan

Let $I$ be a weakly polymatroidal ideal or a squarefree monomial ideal of a polynomial ring $S$. In this paper we provide a lower bound for the Stanley depth of $I$ and $S/I$. In particular we prove that if $I$ is a squarefree monomial…

Commutative Algebra · Mathematics 2013-02-26 S. A. Seyed Fakhari

In this paper, we give a new algebraic criterion for the {\em shellability} of (non-pure) simplicial complex $\Delta$ over $[n]$, shellable in the sense of Bj\"orner and Wachs \cite{BW}. We show that the spanning simplicial complex of…

Commutative Algebra · Mathematics 2017-04-20 Imran Anwar , Zunaira Kosar , Shaheen Nazir , Khurram Shabbir

Recently, H. Dao and R. Nair gave a combinatorial description of simplicial complexes $\Delta$ such that the squarefree reduction of the Stanley-Reisner ideal of $\Delta$ has the WLP in degree $1$ and characteristic zero. In this paper, we…

Commutative Algebra · Mathematics 2023-06-26 Thiago Holleben

Let $\Delta$ be a pure simplicial complex and $I_\Delta$ its Stanley-Reisner ideal in a polynomial ring $S$. We show that $\Delta$ is a matroid (complete intersection) if and only if $S/I_\Delta^{(m)}$ ($S/I_\Delta^m$) is clean for all…

Commutative Algebra · Mathematics 2015-05-05 Somayeh Bandari , Ali Soleyman Jahan

We introduce a notion of lexicographic shellability for pure, balanced boolean cell complexes, modelled after the $CL$-shellability criterion of Bj\"orner and Wachs for posets and its generalization by Kozlov called $CC$-shellability. We…

Combinatorics · Mathematics 2007-05-23 Patricia Hersh

Let $W$ be a Weyl group corresponding to the root system $A_{n-1}$ or $B_n$. We define a simplicial complex $ \Delta^m_W $ in terms of polygon dissections for such a group and any positive integer $m$. For $ m=1 $, $ \Delta^m_W$ is…

Combinatorics · Mathematics 2007-05-23 Eleni Tzanaki

We prove that the Stanley--Reisner ideal of the Alexander dual of the subword complexes in Coxeter groups has linear quotients with respect to the lexicographical order of the minimal monomial generators. As a consequence, we obtain a…

Commutative Algebra · Mathematics 2008-12-01 Anda Olteanu

Let $\mathbb{K}$ be a field and $S=\mathbb{K}[x_1,\dots,x_n]$ be the polynomial ring in $n$ variables over $\mathbb{K}$. Assume that $G$ is a graph with edge ideal $I(G)$. We prove that the modules $S/\overline{I(G)^k}$ and…

Commutative Algebra · Mathematics 2018-08-13 S. A. Seyed Fakhari

We study Stanley decompositions and show that Stanley's conjecture on Stanley decompositions implies his conjecture on partitionable Cohen-Macaulay simplicial complexes. We also prove these conjectures for all Cohen-Macaulay monomial ideals…

Commutative Algebra · Mathematics 2007-05-23 Juergen Herzog , Ali Soleyman Jahan , Siamak Yassemi

We consider ideals $I$ in a Stanley-Reisner ring $k[\Delta]$ over the simplical complex $\Delta$, such that the tight closure of $I$, $I^*$, is equal to $\mathfrak{m}$, the standard graded maximal ideal of $k[\Delta]$. We determine the…

Commutative Algebra · Mathematics 2018-10-25 Thomas M. Ales

Imposing a strong condition on the linear order of shellable complexes, we introduce strong shellability. Basic properties, including the existence of dimension-decreasing strong shelling orders, are developed with respect to nonpure…

Combinatorics · Mathematics 2016-04-20 Jin Guo , Yi-Huang Shen , Tongsuo Wu

Let $\Delta$ be a stable simplicial complex on $n$ vertexes. Over an arbitrary base field $K$, the symmetric algebraic shifted complex $\Delta^s$ of $\Delta$ is defined. It is proved that the Betti numbers of the Stanley-Reisner ideals in…

Commutative Algebra · Mathematics 2007-05-23 Zhongming Tang , Guifen Zhuang

Monomial ideals which are generic with respect to either their generators or irreducible components have minimal free resolutions derived from simplicial complexes. For a generic monomial ideal, the associated primes satisfy a saturated…

Commutative Algebra · Mathematics 2007-05-23 Ezra Miller , Bernd Sturmfels , Kohji Yanagawa

For a graph $G$, Bayer-Denker-Milutinovi\'c-Rowlands-Sundaram-Xue study in \cite{B-D-M-R-S-X} a new graph complex $\Delta_k^t(G)$, namely the simplicial complex with facets that are complements to independent sets of size $k$ in $G$. They…

Commutative Algebra · Mathematics 2023-11-07 Ralf Froberg

Let $\Delta$ be an (abstract) simplicial complex on $n$ vertices. One can define the Artinian monomial algebra $A(\Delta) = \Bbbk[x_1, \ldots, x_n]/ \langle x_1^2, \ldots, x_n^2, I_{\Delta} \rangle$, where $\Bbbk$ is a field of…

Commutative Algebra · Mathematics 2024-03-12 Hailong Dao , Ritika Nair

For each squarefree monomial ideal $I\subset S = k[x_{1},\ldots, x_{n}] $, we associate a simple graph $G_I$ by using the first linear syzygies of $I$. In cases, where $G_I$ is a cycle or a tree, we show the following are equivalent: (a) $…

Commutative Algebra · Mathematics 2018-09-05 Erfan Manouchehri , Ali Soleyman Jahan

We say that a pure $d$-dimensional simplicial complex $\Delta$ on $n$ vertices is \emph{shelling completable} if $\Delta$ can be realized as the initial sequence of some shelling of $\Delta_{n-1}^{(d)}$, the $d$-skeleton of the…

Combinatorics · Mathematics 2023-08-11 Michaela Coleman , Anton Dochtermann , Nathan Geist , Suho Oh