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A local ring $R$ is regular if and only if every finitely generated $R$-module has finite projective dimension. Moreover, the residue field $k$ is a test module: $R$ is regular if and only if $k$ has finite projective dimension. This…

Commutative Algebra · Mathematics 2021-05-14 Benjamin Briggs , Eloísa Grifo , Josh Pollitz

A ring is *unit-additive* if a sum of units is always either a unit or nilpotent. For example, $k[X]$ and $k[X]/(X^2)$ are unit-additive, but $\mathbb Z$ is not. We prove a wide-ranging theorem about unit-additivity in semigroup rings,…

Commutative Algebra · Mathematics 2025-04-22 Neil Epstein , Jay Shapiro

In this paper several characterizations of semi-compact modules are given. Among other results, we study rings whose semi-compact modules are injective. We introduce the property $\Sigma$-semi-compact for modules and we characterize the…

Commutative Algebra · Mathematics 2022-03-08 Mahmood Behboodi , François Couchot , Seyed Hossein Shojaee

We partially answer two questions of Goodaire by showing that in a finite, strongly right alternative ring, the set of units (if the ring is with unity) is a Bol loop under ring multiplication, and the set of quasiregular elements is a Bol…

Rings and Algebras · Mathematics 2025-09-10 Michael Kinyon , J. D. Phillips

Let R be a Cohen-Macaulay local ring possessing a canonical module. In this paper we consider when the maximal ideal of R is self-dual, i.e. it is isomorphic to its canonical dual as an R-module. local rings satisfying this condition are…

Commutative Algebra · Mathematics 2020-10-21 Toshinori Kobayashi

Let $(R,\fm)$ be a Cohen-Macaulay local ring. If $R$ has a canonical module, then there are some interesting results about duality for this situation. In this paper, we show that one can indeed obtain similar these results in the case $R$…

Commutative Algebra · Mathematics 2008-09-25 Mohammad Ali Esmkhani , Massoud Tousi

This article introduces the notion of an NJ-reflexive ring and demonstrates that it is distinct from the concept of a reflexive ring. The class of NJ-reflexive rings contains the class of semicommutative rings, the class of left (right)…

Rings and Algebras · Mathematics 2024-01-30 Sanjiv Subba , Tikaram Subedi

Let $\mathcal{P}$ be the class of rings for which every indecomposable right module is pure-projective or pure-injective. When $R$ is a Noetherian local commutative ring of maximal ideal $P$, it is proven that $R\in\mathcal{P}$ if and only…

Rings and Algebras · Mathematics 2025-07-08 François Couchot

The ideal of relations in the (small) quantum cohomology ring of the generalized flag manifold $G/B$ has been determined by B. Kim. We are going to point out a limited number of properties that, if they are satisfied by an…

Differential Geometry · Mathematics 2007-05-23 A. -L. Mare

Let $R$ be a ring and $S$ a multiplicative subset of $R$. An $R$-module $P$ is called uniformly $S$-projective provided that the induced sequence $0\rightarrow \mathrm{Hom}_R(P,A)\rightarrow \mathrm{Hom}_R(P,B)\rightarrow…

Commutative Algebra · Mathematics 2022-07-25 Xiaolei Zhang , Wei Qi

A regular ordered semigroup $S$ is called right inverse if every principal left ideal of $S$ is generated by an $\mathcal{R}$-unique ordered idempotent. Here we explore the theory of right inverse ordered semigroups. We show that a regular…

Group Theory · Mathematics 2017-06-27 A. Jamadar , K. Hansda

'A semigroup is completely regular if and only if it is a union of groups'- an analogue of this structure theorem of completely regular semigroup has been obtained in the setting of seminearrings in [[16], Mukherjee (Pal) et al., Semigroup…

Rings and Algebras · Mathematics 2025-07-10 Rajlaxmi Mukherjee , Tuhin Manna , Kamalika Chakraborty , Sujit Kumar Sardar

A semiring is uniserial if its ideals are totally ordered by inclusion. First, we show that a semiring $S$ is uniserial if and only if the matrix semiring $M_n(S)$ is uniserial. As a generalization of valuation semirings, we also…

Commutative Algebra · Mathematics 2022-06-22 H. Behzadipour , P. Nasehpour

An ordered semiring is a commutative semiring equipped with a compatible preorder. Ordered semirings generalise both distributive lattices and commutative rings, and provide a convenient framework to unify certain aspects of lattice theory…

Category Theory · Mathematics 2023-11-08 Soichiro Fujii

In a pandemic era preprint, Dao showed showed two remarkable properties of Arf rings: under some mild conditions, they admit finitely many indecomposable reflexive modules up to isomorphism and every reflexive module is actually isomorphic…

Commutative Algebra · Mathematics 2025-05-23 Özgür Esentepe

A ring $R$ is said to be right McCoy if the equation $f(x)g(x)=0,$ where $f(x)$ and $g(x)$ are nonzero polynomials of $R[x],$ implies that there exists nonzero $s \in R$ such that $f(x)s = 0$. It is proven that no proper (triangular) matrix…

Rings and Algebras · Mathematics 2007-08-15 Zhiling Ying , Jianlong Chen , Zhen Lei

We study the notion of Rickart property in a general module theoretic setting as a generalization to the concept of Baer modules and right Rickart rings. A module $M_{R}$ is called Rickart if the right annihilator in $M_{R}$ of each left…

Rings and Algebras · Mathematics 2016-09-15 Ali H. Al-Saedi , Mehdi S. Abbas

For a commutative ring R we investigate the property that the sets of minimal primes of finitely generated ideals of R is always finite. We prove this property passes to polynomial ring extensions (in an arbitrary number of variables) over…

Commutative Algebra · Mathematics 2007-05-23 Thomas Marley

Let $\Gamma$ be a cancellation monoid and $R=\bigoplus_{\alpha \in \Gamma}R_{\alpha}$ be a $\Gamma$-graded ring. It is shown that $R$ is graded left semihereditary if and only if $R$ is graded left coherent and every graded submodule of a…

Rings and Algebras · Mathematics 2026-05-12 Parviz Sahandi , Nematollah Shirmohammadi

It is proven that each commutative arithmetical ring $R$ has a finitistic weak dimension $\leq 2$. More precisely, this dimension is 0 if $R$ is locally IF, 1 if $R$ is locally semicoherent and not IF, and 2 in the other cases.

Commutative Algebra · Mathematics 2012-05-03 Francois Couchot