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We study integrality over rings (all commutative in this paper) and over ideal semifiltrations (a generalization of integrality over ideals). We begin by reproving classical results, such as a version of the "faithful module" criterion for…

Commutative Algebra · Mathematics 2019-07-16 Darij Grinberg

An ideal $I$ in a Noetherian ring is called \textit{normal} if $I^n$ is integrally closed for all $n \geq 1$. Zariski proved that in two-dimensional regular local rings, every integrally closed ideal is normal. However, in dimension three…

Commutative Algebra · Mathematics 2026-02-03 Maki Ataka , Naoyuki Matsuoka

The arithmetic rank of an ideal in a polynomial ring over an algebraically closed field is the smallest number of equations needed to define its vanishing locus set-theoretically. We determine the arithmetic rank of the generic $m$-residual…

Commutative Algebra · Mathematics 2026-04-20 Manav Batavia , Kesavan Mohana Sundaram , Vaibhav Pandey , Taylor Murray

We study properties of the resolution of almost Gorenstein artinian algebras $R/I,$ i.e. algebras defined by ideals $I$ such that $I=J+(f),$ with $J$ Gorenstein ideal and $f\in R.$ Such algebras generalize the well known almost complete…

Algebraic Geometry · Mathematics 2020-02-18 Giuseppe Zappalà

We study the ideals of the closure of the polynomial multipliers on the Drury-Arveson space. Structural results are obtained by investigating the relation between an ideal and its weak-$*$ closure, much in the spirit of the corresponding…

Operator Algebras · Mathematics 2016-06-28 Raphaël Clouâtre , Kenneth R. Davidson

In this note, we propose a generalisation of G. Janelidze's notion of an ideally exact category beyond the Barr exact setting. We define an ideally regular category as a regular, Bourn protomodular category with finite coproducts in which…

Category Theory · Mathematics 2026-03-03 Sandra Mantovani , Mariano Messora

In this paper, we view the collection of ideals of a commutative principal ideal ring from two perspectives: one as an ordered semigroup I(R) and the other as a category I_R . It is shown that I(R) is a regular ordered semigroup whereas I_R…

Rings and Algebras · Mathematics 2026-05-26 P. K. Minnumol , P. G. Romeo

For a discrete group $G$, we use the natural correspondence between ideals in the Boolean algebra $ \mathcal{P}_G$ of subsets of $G$ and closed subsets in the Stone-$\check{C}$ech compactifi-cation $\beta G$ as a right topological semigroup…

General Topology · Mathematics 2017-04-11 Igor Protasov , Ksenia Protasova

The purpose of this note is to revisit the results of arXiv:1407.4324 from a slightly different perspective, outlining how, if the integral closures of a finite set of prime ideals abide the expected convexity patterns, then the existence…

Commutative Algebra · Mathematics 2016-07-06 Matteo Varbaro

Let $R=\oplus_{m\geq 0}R_m$ be a standard graded equidimensional ring over a field $R_0$, and $I\subseteq J$ be two non-nilpotent graded ideals in $R$. Then we give a set of numerical characterizations of the integral dependence of $I$ and…

Commutative Algebra · Mathematics 2025-05-12 Suprajo Das , Sudeshna Roy , Vijaylaxmi Trivedi

$(1)$ Let $M\subset N$ be a commutative cancellative torsion-free and subintegral extension of monoids. Then we prove that in the case of ring extension $A[M]\subset A[N]$, the two notions, subintegral and weakly subintegral coincide…

Commutative Algebra · Mathematics 2025-07-21 Md Abu Raihan , Leslie G. Roberts , Husney Parvez Sarwar

In order to simultaneously generalize matrix rings and group graded crossed products, we introduce category crossed products. For such algebras we describe the center and the commutant of the coefficient ring. We also investigate the…

Rings and Algebras · Mathematics 2008-12-09 Johan Öinert , Patrik Lundström

We define a duality operation connecting closure operations, interior operations, and test ideals, and describe how the duality acts on common constructions such as trace, torsion, tight and integral closures, and divisible submodules. This…

Commutative Algebra · Mathematics 2021-04-26 Neil Epstein , R. G. Rebecca

Using results obtained from the study of homogeneous ideals sharing the same initial ideal with respect to some term order, we prove the singularity of the point corresponding to a segment ideal with respect to the revlex term order in the…

Commutative Algebra · Mathematics 2010-03-16 Francesca Cioffi , Paolo Lella , Maria Grazia Marinari , Margherita Roggero

An ideal is a classical object of study in the field of algebraic number theory. In maximal quadratic orders of number fields, ideals usually represented by the $\mathbb Z$-basis. This form of representation is used in most of the…

Number Theory · Mathematics 2014-02-11 Anton S. Mosunov

Let $I_G$ be the binomial edge ideal on the generic 2 x n - Hankel matrix associated with a closed graph $G$ on the vertex set [n]. We characterize the graphs $G$ for which $I_G$ has maximal regularity and is Gorenstein.

Commutative Algebra · Mathematics 2015-12-02 Ahmet Dokuyucu , Ajdin Halilovic , Rida Irfan

Let $R$ be a commutative ring with identity. An ideal $I$ of $R$ is said to be a big ideal (resp. an upper big ideal) if whenever $J\subsetneqq I$ (resp. $I\subsetneqq J$), $J^{n}\subsetneqq I^{n}$ (resp. $I^{n}\subsetneqq J^{n}$) for every…

Commutative Algebra · Mathematics 2022-03-10 Abdeslam Mimouni

The notion of $p_g$-ideals for normal surface singularities has been proved to be very useful. On the other hand, the core of ideals has been proved to be very important concept and also very mysterious one. However, the computation of the…

Algebraic Geometry · Mathematics 2025-12-16 Tomohiro Okuma , Kei-ichi Watanabe , Ken-ichi Yoshida

The properties of the intersection algebra of two principal monomial ideals in a polynomial ring are investigated in detail. Results are obtained regarding the Hilbert series and the canonical ideal of the intersection algebra using methods…

Commutative Algebra · Mathematics 2014-09-05 Florian Enescu , Sara Malec

A quasi-complete intersection (q.c.i.) ideal of a local ring is an ideal with "free exterior Koszul homology"; the definition can also be understood in terms of vanishing of Andr\'e-Quillen homology functors. Principal q.c.i. ideals are…

Commutative Algebra · Mathematics 2015-01-07 Andrew R. Kustin , Liana M. Şega , Adela Vraciu