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Related papers: The Structure of Ulrich ideals in hypersurfaces

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In this paper we study Ulrich ideals of and Ulrich modules over Cohen--Macaulay local rings from various points of view. We determine the structure of minimal free resolutions of Ulrich modules and their associated graded modules, and…

Commutative Algebra · Mathematics 2013-06-07 Shiro Goto , Kazuho Ozeki , Ryo Takahashi , Kei-ichi Watanabe , Ken-ichi Yoshida

The structure of the complex $\operatorname{\mathbf{R}Hom}_R(R/I,R)$ is explored for an Ulrich ideal $I$ in a Cohen-Macaulay local ring $R$. As a consequence, it is proved that in a one-dimensional almost Gorenstein but non-Gorenstein local…

Commutative Algebra · Mathematics 2016-05-17 Shiro Goto , Ryo Takahashi , Naoki Taniguchi

The Ulrich ideals in the semigroup rings $k[[t^5, t^{11}]]$ and $k[[t^5,t^6,t^9]]$ are determined, by describing the normal forms of systems of generators, where $k[[t]]$ denotes the formal power series ring over a field $k$.

Commutative Algebra · Mathematics 2021-11-02 Naoki Endo , Shiro Goto , Shin-ichiro Iai , Naoyuki Matsuoka

This paper studies Ulrich ideals in one-dimensional Cohen-Macaulay local rings. A correspondence between Ulrich ideals and overrings is given. Using the correspondence, chains of Ulrich ideals are closely explored. The specific cases where…

Commutative Algebra · Mathematics 2018-04-19 Shiro Goto , Ryotaro Isobe , Shinya Kumashiro

We study the projective normality of the projective bundle of an Ulrich vector bundle embedded through the complete linear system of its tautological line bundle. The focus will be on Ulrich bundles defined over curves, surfaces with…

Algebraic Geometry · Mathematics 2024-12-23 Valerio Buttinelli

Let $R=k[x_1, ..., x_n]/(x_1^d + ... + x_n^d)$, where $k$ is a field of characteristic $p$, $p$ does not divide $d$ and $n \geq 3$. We describe a method for computing the test ideal for these diagonal hypersurface rings. This method…

Commutative Algebra · Mathematics 2007-05-23 Moira A. McDermott

The main aim of this paper is to classify Ulrich ideals and Ulrich modules over two-dimensional Gorenstein rational singularities (rational double points) from a geometric point of view. To achieve this purpose, we introduce the notion of…

Commutative Algebra · Mathematics 2013-07-09 Shiro Goto , Kazuho Ozeki , Ryo Takahashi , Kei-ichi Watanabe , Ken-ichi Yoshida

We revisit Allendoerfer-Weil's formula for the Euler characteristic of embedded hypersurfaces in constant sectional curvature manifolds, first taking some time to re-prove it while demonstrating techniques of [2] and then applying it to…

Differential Geometry · Mathematics 2021-09-08 R. Albuquerque

This study investigates the structure of Arf rings. From the perspective of ring extensions, a decomposition of integrally closed ideals is given. Using this, we present a kind of their prime ideal decomposition in Arf rings, and determine…

Commutative Algebra · Mathematics 2022-02-07 Ryotaro Isobe

Ulrich ideals in numerical semigroup rings of small multiplicity are studied. If the semigroups are three-generated but not symmetric, the semigroup rings are Golod, since the Betti numbers of the residue class fields of the semigroup rings…

Commutative Algebra · Mathematics 2021-11-02 Naoki Endo , Shiro Goto

In this paper we further develop the theory of generalized Ulrich modules introduced in 2014 by Goto et al. Our main goal is to address the problem of when the operations of taking the Hom functor and horizontal linkage preserve the Ulrich…

Commutative Algebra · Mathematics 2023-03-21 Cleto B. Miranda-Neto , Douglas S. Queiroz , Thyago S. Souza

We continue our study of F-thresholds begun in math/0607660 by an in depth analysis of the hypersurface case. We use the D--module theoretic description of generalized test ideals which allows us to show that in any F--finite regular ring…

Algebraic Geometry · Mathematics 2011-02-18 Manuel Blickle , Mircea Mustaţǎ , Karen Smith

The acquisition of the defining equations of Rees algebras is a natural way to study these algebras and allows certain invariants and properties to be deduced. In this paper, we consider Rees algebras of codimension 2 perfect ideals of…

Commutative Algebra · Mathematics 2021-12-07 Matthew Weaver

We introduce primitive hyperideals of a hyperring R and show relations with R itself, and with maximal and prime hyperideals of R. We endow a Jacobson topology on the set of primitive hyperideals of R and study topological properties of the…

Rings and Algebras · Mathematics 2023-01-02 Bijan Davvaz , Amartya Goswami , Karin-Therese Howell

Let $H\subseteq \mathbb{N}^d$ be a normal affine semigroup, $R=K[H]$ its semigroup ring over the field $K$ and $\omega_R$ its canonical module. The Ulrich elements for $H$ are those $h$ in $H$ such that for the multiplication map by…

Commutative Algebra · Mathematics 2021-01-22 Jürgen Herzog , Raheleh Jafari , Dumitru I. Stamate

This work provides a curve-based approach to Ulrich bundles on surfaces, establishing a correspondence that characterizes their existence, with a focus on applications to surfaces in $\mathbb{P}^3$.

Algebraic Geometry · Mathematics 2025-10-16 Sofia Bordoni

This paper mainly focuses on commutative local domains of dimension one. We then obtain a criterion for a ring to have a finite number of trace ideals in terms of integrally closed ideals. We also explore properties of such rings related to…

Commutative Algebra · Mathematics 2022-03-10 Toshinori Kobayashi , Shinya Kumashiro

In this work we characterize Ulrich bundles of any rank on polarized rational ruled surfaces over $\mathbb{P}^1$. We show that every Ulrich bundle admits a resolution in terms of line bundles. Conversely, given an injective map between…

Algebraic Geometry · Mathematics 2020-03-12 Vincenzo Antonelli

A Lie hypersurface in the complex hyperbolic space is a homogeneous real hypersurface without focal submanifolds. The set of all Lie hypersurfaces in the complex hyperbolic space is bijective to a closed interval, which gives a deformation…

Differential Geometry · Mathematics 2009-08-25 Tatsuyoshi Hamada , Yuji Hoshikawa , Hiroshi Tamaru

This paper investigates Ulrich bundles on decomposable threefold scrolls X over the Hirzebruch surface $\mathbb F_a$, for any integer $a \geq 0$, focusing on the study of their structure and classification. We prove existence of such Ulrich…

Algebraic Geometry · Mathematics 2025-07-15 Maria Lucia Fania , Flaminio Flamini , Francesco Malaspina , Joan Pons-Llopis
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