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We prove that every orbit of the adjoint representation of any connected reductive algebraic group $G$ is a rational algebraic variety. For complex simply connected semisimple $G$, this implies rationality of affine Hamiltonian…

Algebraic Geometry · Mathematics 2022-06-29 Vladimir L. Popov

Let I be a finitely supported complete m-primary ideal of a regular local ring (R, m). A theorem of Lipman implies that I has a unique factorization as a *-product of special *-simple complete ideals with possibly negative exponents for…

Commutative Algebra · Mathematics 2014-01-15 William Heinzer , Mee-Kyoung Kim , Matthew Toeniskoetter

We describe the endomorphism ring of a short exact sequences $0 \to A_R \to B_R \to C_R \to 0$ with $A_R$ and $C_R$ uniserial modules and the behavior of these short exact sequences as far as their direct sums are concerned.

Rings and Algebras · Mathematics 2025-04-18 Federico Campanini , Alberto Facchini

For any ring \(R\), some characterizations are obtained for unit regular elements in a corner ring \(eRe\) in terms of unit regular elements in \(R\). \noindent {\bf Key Words}: von Neumann regular rings, unit regular rings, corner rings,…

Rings and Algebras · Mathematics 2014-02-26 T. Y. Lam , Will Murray

This article studies the notion of $S-r-$ideals in commutative ring $H$, where $S$ is a multiplicatively closed subset of $H$. Some basic properties of $S-r-$ideals are given. Various characterizations of $S-r-$ideals are presented. Also,…

Commutative Algebra · Mathematics 2025-09-16 Abuzer Gündüz , Osama A. Naji , Mehmet Özen

We define the rank of elements of general unital rings, discuss its properties and give several examples to support the definition. In semiprime rings we give a characterization of rank in terms of invertible elements. As an application we…

Rings and Algebras · Mathematics 2023-08-28 Nik Stopar

An interchange ring,(R,+,*)is an abelian group with a second binary operation defined so that the interchange law (x+y)*(u+v)=(x*u)+(y*v)holds. An interchange near ring is the same structure based on a group which may not be abelian. It is…

Rings and Algebras · Mathematics 2016-05-18 Charles Edmunds

Let $k$ be a field with characteristic zero, $R$ be the ring $k[x_1, \cdots, x_n]$ and $I$ be a monomial ideal of $R$. We study the Artinian local algebra $R/I$ when considered as an $R$-module $M$. We show that the largest reduced…

Commutative Algebra · Mathematics 2023-07-14 Tilahun Abebaw , Nega Arega , Teklemichael Worku Bihonegn , David Ssevviiri

Let $R$ be a commutative ring with unity. The prime ideal sum graph of the ring $R$ is the simple undirected graph whose vertex set is the set of all nonzero proper ideals of $R$ and two distinct vertices $I$, $J$ are adjacent if and only…

Combinatorics · Mathematics 2023-07-20 Praveen Mathil , Jitender Kumar

We classify irreducible representations of connected compact Lie groups whose orbit space is isometric to the orbit space of a representation of a finite extension of (positive dimensional) toric group. They turn out to be exactly the…

Differential Geometry · Mathematics 2012-12-27 Claudio Gorodski , Alexander Lytchak

Noetherian rings have played a fundamental role in commutative algebra, algebraic number theory, and algebraic geometry. Along with their dual, Artinian rings, they have many generalizations, including the notions of isonoetherian and…

Commutative Algebra · Mathematics 2024-10-14 Asghar Daneshvar , Kamran Divaani-Aazar

Let R be an unramified regular local ring of mixed characteristic, D an Azumaya R-algebra, K the fraction field of R, Nrd the reduced norm homomorphism for the Azumaya R-algebra D. Let a be a unit in R. It is proved the following: suppose…

K-Theory and Homology · Mathematics 2022-02-14 Ivan Panin

Let R be a commutative noetherian ring. Lindo and Pande have recently posed the question asking when every ideal of R is isomorphic to some trace ideal of R. This paper studies this question and gives several answers. In particular, a…

Commutative Algebra · Mathematics 2018-07-17 Toshinori Kobayashi , Ryo Takahashi

Let $A$ be a commutative noetherian ring and $I$ an ideal in $A$. We characterize algebraically when all the minimal primes of the associated graded ring $G_I A$ contract to minimal primes of $A/I$. This, applied to intersection theory,…

Commutative Algebra · Mathematics 2007-05-23 Erika Giorgi

Given a ring $R$, we study the bimodules $M$ for which the trivial extension $R\propto M$ is morphic. We obtain a complete characterization in the case where $R$ is left perfect, and we prove that $R\propto Q/R$ is morphic when $R$ is a…

Rings and Algebras · Mathematics 2009-07-08 Alexander J. Diesl , Thomas J. Dorsey , Warren Wm. McGovern

Irreducible decompositions of monomial ideals in polynomial rings over a field are well-understood. In this paper, we investigate decompositions in the set of monomial ideals in the semigroup ring A[\mathbb{R}_{\geq 0}^d] where A is an…

Commutative Algebra · Mathematics 2012-05-21 Daniel Ingebretson , Sean Sather-Wagstaff

We discuss a certain class of absolutely irreducible group representations that behave nicely under the restriction to normal subgroups and subalgebras. These representations proved to be useful for the construction of abelian varieties…

Group Theory · Mathematics 2007-05-23 Yuri G. Zarhin

A ring $R$ with an involution * is called (strongly) *-clean if every element of $R$ is the sum of a unit and a projection (that commute). All *-clean rings are clean. Va${\rm \check{s}}$ [L. Va${\rm \check{s}}$, *-Clean rings; some clean…

Rings and Algebras · Mathematics 2011-07-07 Jianlong Chen , Jian Cui

Let $R$ be a $d$-dimensional standard graded ring over an Artin local ring. Let $M$ be the unique maximal homogeneous ideal of $R.$ Let $h^i(R)_n$ denote the length of $H^i_M(R)_n$, i.e. the nth graded component of the ith local cohomology…

Commutative Algebra · Mathematics 2007-05-23 Clare D'Cruz , Vijay Kodiyalam , Jugal. K. Verma

We consider rings whose one-sided ideals are close to automorphism-invariant modules. We study rings in which every (finitely generated) right ideal is automorphism invariant and rings in which every right ideal is a finite direct sum of…

Rings and Algebras · Mathematics 2022-12-13 Adel Abyzov , Truong Cong Quynh , Askar Tuganbaev