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We investigate the structure of ideals generated by binomials (polynomials with at most two terms) and the schemes and varieties associated to them. The class of binomial ideals contains many classical examples from algebraic geometry, and…

alg-geom · Mathematics 2008-02-03 David Eisenbud , Bernd Sturmfels

If $R$ is a topological ring then $R^{\ast}$, the group of units of $R$, with the subspace topology is not necessarily a topological group. This leads us to the following natural definition: By an \emph{absolute topological ring} we mean a…

Commutative Algebra · Mathematics 2025-05-23 Abolfazl Tarizadeh

We analyze the effective content of countable, second countable topological spaces by directly calculating the complexity of several topologically defined index sets. We focus on the separation principles, calibrating an arithmetic…

Logic · Mathematics 2025-07-25 Andrew DeLapo , David Gonzalez

To each monoid $P$ that embeds in a group we associate a universal Toeplitz C*-algebra $T_u(P)$ defined via generators and relations; $T_u(P)$ is a quotient of Li's semigroup C*-algebra $C^*(P)$ and they are isomorphic if and only if $P$…

Operator Algebras · Mathematics 2022-05-31 Marcelo Laca , Camila F. Sehnem

This paper introduce and study weakly 1-absorbing prime ideals in commutative rings. Let $A$ be a commutative ring with a nonzero identity $1\neq 0$. A proper ideal $P$ of $A$ is said to be a weakly 1-absorbing prime ideal if for each…

Commutative Algebra · Mathematics 2020-05-22 Suat Koç , Ünsal Tekir , Eda Yıldız

Given a tree T on n vertices, there is an associated ideal I of a polynomial ring in n variables over a field, generated by all paths of a fixed length of T. We show that such an ideal always satisfies the Konig property and classify all…

Commutative Algebra · Mathematics 2012-11-21 Daniel Campos , Ryan Gunderson , Susan Morey , Chelsey Paulsen , Thomas Polstra

Let (A,G) be a C*-dynamical system with G discrete. In this paper we investigate the ideal structure of the reduced crossed product C*-algebra and in particular we determine sufficient - and in some cases also necessary - conditions for A…

Operator Algebras · Mathematics 2009-03-16 Adam Sierakowski

We introduce the $\ell^1$-ideal intersection property for crossed product C*-algebras. It is implied by C*-simplicity as well as C*-uniqueness. We show that topological dynamical systems of arbitrary lattices in connected Lie groups,…

Operator Algebras · Mathematics 2026-01-14 Are Austad , Sven Raum

Let $X=(x_{ij})_{m\times n}$ be a matrix of indeterminates and let $S=\mathbb{k}[x_{ij} \mid 1\leq i\leq m,\ 1\leq j\leq n]$ be a polynomial ring over an infinite field $\mathbb{k}$. Let $I$ be an ideal generated by a subset of the set of…

Commutative Algebra · Mathematics 2026-01-27 Omkar Javadekar

In this paper, we introduce a new generalization of weakly prime ideals called $I$-prime. Suppose $R$ is a commutative ring with identity and $I$ a fixed ideal of $R$. A proper ideal $P$ of $R$ is $I$-prime if for $a, b \in R$ with $ab \in…

Commutative Algebra · Mathematics 2017-01-24 Ismael Akray

The aim of this article is to study the ideal class monoid $\mathcal{C}\ell(S)$ of a numerical semigroup $S$ introduced by V. Barucci and F. Khouja. We prove new bounds on the cardinality of $\mathcal{C}\ell(S)$. We observe that…

Commutative Algebra · Mathematics 2023-02-23 Laura Casabella , Marco D'Anna , Pedro A. García-Sánchez

We call a space $X$ {\it weakly linearly Lindel\"of} if for any family $\mathcal{U}$ of non-empty open subsets of $X$ of regular uncountable cardinality $\kappa$, there exists a point $x\in X$ such that every neighborhood of $x$ meets…

General Topology · Mathematics 2016-10-17 I. Juhász , V. V. Tkachuk , R. G. Wilson

The closed one-sided ideals of a C*-algebra are exactly the closed subspaces supported by the orthogonal complement of a closed projection. Let A be a (not necessarily selfadjoint) subalgebra of a unital C*-algebra B which contains the unit…

Operator Algebras · Mathematics 2007-05-23 Damon M. Hay

A ballean $\mathcal{B}$ (or a coarse structure) on a set $X$ is a family of subsets of $X$ called balls (or entourages of the diagonal in $X\times X$) defined in such a way that $\mathcal{B}$ can be considered as the asymptotic counterpart…

General Topology · Mathematics 2019-02-06 D. Dikranjan , I. Protasov , K. Protasova , N. Zava

We define a unital algebra $A$ over a field $\mathbb{F}$ to be nearly simple if $A$ contains a unique non-trivial ideal $I_A$ such that $I_A^2 \neq \{0\}$. If $A$ and $B$ are two nearly simple algebras, we consider the ideal structure of…

Rings and Algebras · Mathematics 2020-01-01 Ilja Gogić

We consider here one-parameter semigroups ${\bf T}=(T(t))_{t>0}$ of bounded operators on a Banach space $X$ which are weakly continuous in the sense of Arveson. For such a semigroup ${\bf T}$ denote by ${\mathcal M}_{\omega_{\bf T}}$ the…

Functional Analysis · Mathematics 2017-09-18 Jean Esterle

A homogeneous ideal is robust if its universal Gr\"obner basis is also a minimal generating set. For toric ideals, one has the stronger definition: A toric ideal is strongly robust if its Graver basis equals the set of indispensable…

Commutative Algebra · Mathematics 2017-04-03 Seth Sullivant

Value semigroups of non irreducible singular algebraic curves and their fractional ideals are submonoids of $\mathbb Z^n$ that are closed under infimums, have a conductor and fulfill a special compatibility property on their elements.…

Commutative Algebra · Mathematics 2017-09-11 Marco D'Anna , Pedro A. García-Sánchez , Vincenzo Micale , Laura Tozzo

Closed graphs have been characterized by Herzog et al. as the graphs whose binomial edge ideals have a quadratic Gr\"obner basis with respect to a diagonal term order. In this paper, we focus on a generalization of closed graphs, namely…

Commutative Algebra · Mathematics 2022-08-30 Lisa Seccia

We investigate to what extent we can descend the classification of localizing, smashing and thick ideals in a presentably symmetric monoidal stable $\infty$-category $\mathscr{C}$ along a descendable commutative algebra $A$. We establish…

Category Theory · Mathematics 2023-05-04 Tobias Barthel , Natalia Castellana , Drew Heard , Niko Naumann , Luca Pol , Beren Sanders