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We investigate sets of the common zeros of non-constant semi-invariants for regular modules over canonical algebras. In particular, we show that if the considered algebra is tame then for big enough vectors these sets are complete…

Representation Theory · Mathematics 2007-10-23 Grzegorz Bobinski

Fix an integer $n \geq 1$, and consider the set of all connected finite simple graphs on $n$ vertices. For each $G$ in this set, let $I(G)$ denote the edge ideal of $G$ in the polynomial ring $R = K[x_1,\ldots,x_n]$. We initiate a study of…

Combinatorics · Mathematics 2020-03-18 Takayuki Hibi , Kyouko Kimura , Kazunori Matsuda , Adam Van Tuyl

In this paper we study the Castelnuovo-Mumford regularity of the path ideals of finite simple graphs. We find new upper bounds for various path ideals of gap free graphs. In particular we prove that the path ideals of gap free and claw…

Commutative Algebra · Mathematics 2014-09-15 Arindam Banerjee

In this article, we study bounded-below locally finite $\mathbb{Z}$-graded algebras, which are referred to as commonly graded algebras in literature. Commonly graded algebras have almost similar theory as that of connected graded algebras,…

Rings and Algebras · Mathematics 2025-08-11 Haonan Li , Quanshui Wu

A long standing conjecture, known to us as the Eisenbud Goto conjecture, states that an n-dimensional variety embedded with degree $d$ in the $N$- dimensional projective space is $(d-(N-n)+1)$-regular in the sense of Castelnuovo-Mumford. In…

alg-geom · Mathematics 2007-05-23 Alberto Alzati , Gian Mario Besana

We derive lower und upper bounds for the degree of regularity of an overdetermined, zero-dimensional and homogeneous quadratic semi-regular system of polynomial equations. The analysis is based on the interpretation of the associated…

Combinatorics · Mathematics 2020-11-25 Stavros Kousidis

We introduce and study a notion of Castelnuovo-Mumford regularity suitable for scrolls obtained as projectivisations of sums of line bundles on $\mathbb P^m$. We show that this is a natural generalisation of the well known regularity on…

Algebraic Geometry · Mathematics 2025-01-14 F. Malaspina , G. Sankaran

We define the concept of regularity for bigraded modules and bigraded polynomial ring. In this setting we prove analogs of some of the classical results on $m$-regularity for graded modules over polynomial algebras.

Algebraic Geometry · Mathematics 2007-05-23 J. William Hoffman , Hao Hao Wang

We studies the nearly Gorenstein property for Veronese subalgebras of (semi-)standard graded algebras. We introduce a condition~$(\natural)$ for Cohen--Macaulay semi-standard graded rings, motivated by the study of Ehrhart rings. We show…

Commutative Algebra · Mathematics 2026-01-13 Sora Miyashita

Let $S_\alpha = k\langle x_1,\dots,x_n\rangle /(x_i x_j - \alpha_{ij} x_j x_i)$ be a standard graded skew polynomial algebra over an algebraically closed field $k$ of characteristic not equal to $2$. We show the following results. When $n$…

Rings and Algebras · Mathematics 2026-04-09 Tomoya Oshio , Kenta Ueyama

We compare, for smooth monomial projective curves, the Castel- nuovo-Mumford regularity and the reduction number; we present an example where these two numbers differ. However, we show they coin- cide for a certain class of monomial curves.…

Commutative Algebra · Mathematics 2007-10-25 Michael Hellus , Lê Tuân Hoa , Jürgen Stückrad

We study the arithmetic of seminormal $v$-noetherian weakly Krull monoids with nontrivial conductor which have finite class group and prime divisors in all classes. These monoids include seminormal orders in holomorphy rings in global…

Commutative Algebra · Mathematics 2015-08-05 Alfred Geroldinger , Florian Kainrath , Andreas Reinhart

We give bounds on the Castelnuovo-Mumford regularity of the associated graded module of an arbitrary good filtration and of its fiber cone. These bounds extend previous results of Rossi-Trung-Valla and Linh.

Commutative Algebra · Mathematics 2011-03-18 Le Xuan Dung , Le Tuan Hoa

We call a (simple) graph G codismantlable if either it has no edges or else it has a codominated vertex x, meaning that the closed neighborhood of x contains that of one of its neighbor, such that G-x codismantlable. We prove that if G is…

Combinatorics · Mathematics 2014-01-22 Turker Biyikoglu , Yusuf Civan

We present algorithms for the computation of the Castelnuovo-Mumford regularity of the Rees algebra and of the fiber ring of equigenerated $\mm$-primary ideals in two variables. Applying these algorithms, we find a counter-example to a…

Commutative Algebra · Mathematics 2019-04-17 Dinh Thanh Trung

In this paper we present two independent computational proofs that the monoid derived from $5\times 5\times 3$ contingency tables is normal, completing the classification by Hibi and Ohsugi. We show that Vlach's vector disproving normality…

Combinatorics · Mathematics 2010-01-26 Winfried Bruns , Raymond Hemmecke , Bogdan Ichim , Matthias Koeppe , Christof Soeger

A graph $\Gamma$ is said to be a semi-Cayley graph over a group $G$ if it admits $G$ as a semiregular automorphism group with two orbits of equal size. We say that $\Gamma$ is normal if $G$ is a normal subgroup of ${\rm Aut}(\Gamma)$. We…

Combinatorics · Mathematics 2020-04-22 Majid Arezoomand , Mohsen Ghasemi

We present new combinatorial insights into the calculation of (Castelnuovo-Mumford) regularity of graphs.

Combinatorics · Mathematics 2015-03-23 Turker Biyikoglu , Yusuf Civan

Connected bipartite graphs whose binomial edge ideals are Cohen--Macaulay have been classified by Bolognini et al. In this paper, we compute the depth, Castelnuovo--Mumford regularity, and dimension of the generalized binomial edge ideals…

Commutative Algebra · Mathematics 2023-05-10 Yi-Huang Shen , Guangjun Zhu

We study the Rees algebra of a perfect Gorenstein ideal of codimension 3 in a hypersurface ring. We provide a minimal generating set of the defining ideal of these rings by introducing a modified Jacobian dual and applying a recursive…

Commutative Algebra · Mathematics 2023-01-18 Matthew Weaver