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We present combinatorial characterizations for the associated primes of the second power of squarefree monomial ideals and criteria for this power to have positive depth or depth greater than one.

Commutative Algebra · Mathematics 2013-10-22 Naoki Terai , Ngo Viet Trung

Two-dimensional squarefree monomial ideals can be seen as the Stanley-Reisner ideals of graphs. The main results of this paper are combinatorial characterizations for the Cohen-Macaulayness of ordinary and symbolic powers of such an ideal…

Commutative Algebra · Mathematics 2010-03-11 Nguyen Cong Minh , Ngo Viet Trung

We generalize the concept of a cycle from graphs to simplicial complexes. We show that a simplicial cycle is either a sequence of facets connected in the shape of a circle, or is a cone over such a structure. We show that a simplicial tree…

Commutative Algebra · Mathematics 2007-05-23 Massimo Caboara , Sara Faridi , Peter Selinger

The index of a graded ideal measures the number of linear steps in the graded minimal free resolution of the ideal. In this paper we study the index of powers and squarefree powers of edge ideals. Our results indicate that the index as a…

Commutative Algebra · Mathematics 2021-03-17 Mina Bigdeli , Juergen Herzog , Rashid Zaare-Nahandi

Let $G$ be a finite simple graph and let $I(G)$ denote its edge ideal. For $q \ge 1$, the $q$-th squarefree power $I(G)^{[q]}$ is generated by squarefree monomials corresponding to matchings of size $q$ in $G$. We denote by…

Commutative Algebra · Mathematics 2026-04-21 Sanjoy Das , Arka Ghosh , S Selvaraja

Let $\mathbb{K}$ be a field and $I$ be a square-free monomial ideal in the polynomial ring $\mathbb{K}[x_1, \ldots, x_n]$. The Green-Lazarsfeld index, $\mathrm{index}(I)$, counts the number of steps to reach to a syzygy minimally generated…

Commutative Algebra · Mathematics 2022-09-22 Mohammad Farrokhi Derakhshandeh Ghouchan , Yasin Sadegh , Ali Akbar Yazdan Pour

We prove that hypersurfaces defined by irreducible square-free polynomials have rational singularities. As an easy consequence, we deduce that certain (possibly non-square-free) polynomials associated to pairs of square-free polynomials…

Algebraic Geometry · Mathematics 2025-05-13 Daniel Bath , Mircea Mustaţă , Uli Walther

We study monomial ideals using the operation polarization to first turn them into square-free monomial ideals. We focus on monomial ideals whose polarization produce simplicial trees, and show that many of the properties of simplicial trees…

Commutative Algebra · Mathematics 2017-03-13 Sara Faridi

We define the uniform face ideal of a simplicial complex with respect to an ordered proper vertex colouring of the complex. This ideal is a monomial ideal which is generally not squarefree. We show that such a monomial ideal has a linear…

Combinatorics · Mathematics 2013-08-07 David Cook

In this paper, we study different generalizations of the notion of squarefreeness for ideals to the more general case of modules. We describe the cones of Hilbert functions for squarefree modules in general and those generated in degree…

Commutative Algebra · Mathematics 2012-01-05 Cristina Bertone , Dang Hop Nguyen , Kathrin Vorwerk

For the almost complete intersection ideals $(x_1^2, \dots, x_n^2, (x_1 + \cdots + x_n)^k)$, we compute their reduced Gr\"obner basis for any term ordering, revealing a combinatorial structure linked to lattice paths, elementary symmetric…

Let $S=K[x_1,\dots,x_n]$ be the polynomial ring over a field $K$ and $I\subset S$ be a squarefree monomial ideal generated in degree $n-2$. Motivated by the remarkable behavior of the powers of $I$ when $I$ admits a linear resolution, as…

Commutative Algebra · Mathematics 2025-08-28 Antonino Ficarra , Somayeh Moradi

We introduce the abstract notion of squarefree-power-like functions, which unify the sequences of squarefree ordinary and symbolic powers of squarefree monomial ideals. By employing the Tor-vanishing criteria for mixed sums of ideals, we…

Commutative Algebra · Mathematics 2025-10-17 Trung Chau , Kanoy Kumar Das , Amit Roy , Kamalesh Saha

In this paper, we introduce and study families of squarefree monomial ideals called clique ideals and independence ideals that can be associated to a finite graph. A family of clique ideals with linear resolutions has been characterized.…

Commutative Algebra · Mathematics 2017-12-05 Somayeh Moradi

We consider powers of lexsegment ideals with a linear resolution (equivalently, with linear quotients) which are not completely lexsegment ideals. We give a complete description of their minimal graded free resolution.

Commutative Algebra · Mathematics 2012-06-29 Anda Olteanu

Assume that $G$ is a graph with edge ideal $I(G)$. For every integer $s\geq 1$, we denote the squarefree part of the $s$-th symbolic power of $I(G)$ by $I(G)^{\{s\}}$. We determine an upper bound for the regularity of $I(G)^{\{s\}}$ when…

Commutative Algebra · Mathematics 2023-03-07 S. A. Seyed Fakhari

Let $I\subset R=K[x_1, \ldots, x_n]$ be a square-free monomial ideal, $\mathfrak{q}$ be a prime monomial ideal in $R$, $h$ be a square-free monomial in $R$ with $\mathrm{supp}(h) \cap (\mathrm{supp}(\mathfrak{q}) \cup…

Commutative Algebra · Mathematics 2024-04-25 Mehrdad Nasernejad , Veronica Crispin Quiñonez , Winfried Hochstättler

Let $I(G)$ be the edge ideal of a simple graph $G$. We prove that $I(G)^2$ has a linear free resolution if and only if $G$ is gap-free and reg$I(G) \le 3$. Similarly, we show that $I(G)^3$ has a linear free resolution if and only if $G$ is…

Commutative Algebra · Mathematics 2022-10-11 Nguyen Cong Minh , Thanh Vu

Let $R = k[x_1, \dotsc , x_n]$ denote the standard graded polynomial ring over a field $k$. We study certain classes of equigenerated monomial ideals with the property that the so-called complementary ideal has no linear relations on the…

Commutative Algebra · Mathematics 2022-01-27 Keller VandeBogert

We study the symbolic powers of square-free monomial ideals via symbolic Rees algebras and methods in prime characteristic. In particular, we prove that the symbolic Rees algebra and the symbolic associated graded algebra are split with…

Commutative Algebra · Mathematics 2019-07-29 Jonathan Montaño , Luis Núñez-Betancourt