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We consider the smallest subring $D$ of $\mathbb{R}(X)$ containing every element of the form $1/(1+x^2)$, with $x\in \mathbb{R}(X)$. $D$ is a Pr\"ufer domain called the minimal Dress ring of $\mathbb{R}(X)$. In this paper, addressing a…

Commutative Algebra · Mathematics 2023-12-14 Laura Cossu

In 2020, Cossu and Zanardo raised a conjecture on the idempotent factorization on singular matrices in the form $\begin{pmatrix} p&z\\ \bar{z}&\sfrac{\lVert z\rVert}{p} \end{pmatrix},$ where $p$ is a prime integer which is irreducible but…

Rings and Algebras · Mathematics 2023-06-02 Peeraphat Gatephan , Kijti Rodtes

Let $k = \mathbb{Q}(\sqrt{\alpha})$ be a real quadratic number field, where $\alpha$ is a positive square-free integer. Let $\mathcal{O}_k$ be the ring of integers of $k$. In this paper, we prove that a certain set of $2 \times 2$ singular…

Number Theory · Mathematics 2020-06-02 Dong Quan Ngoc Nguyen

Let $A_1,\ldots,A_s$ be unitary commutative rings which do not have non-trivial idempotents and let $A=A_1\oplus\cdots\oplus A_s$ be their direct sum. We describe all idempotents in the $2\times 2$ matrix ring $M_2(A[[X]])$ over the ring…

Rings and Algebras · Mathematics 2020-06-29 Vesselin Drensky

Given an element $f$ in a regular local ring, we study matrix factorizations of $f$ with $d \ge 2$ factors, that is, we study tuples of square matrices $(\varphi_1,\varphi_2,\dots,\varphi_d)$ such that their product is $f$ times an identity…

Commutative Algebra · Mathematics 2021-02-16 Tim Tribone

In this paper we provide concrete constructions of idempotents to represent typical singular matrices over a given ring as a product of idempotents and apply these factorizations for proving our main results. We generalize works due to…

Rings and Algebras · Mathematics 2013-02-05 Adel Alahmadi , Surender Jain , André Leroy

A classical problem, that goes back to the 1960's, is to characterize the integral domains R satisfying the property (IDn): "every singular nxn matrix over R is a product of idempotent matrices". Significant results, which describe this…

Commutative Algebra · Mathematics 2023-12-14 Laura Cossu , Paolo Zanardo

Idempotent elements play a fundamental role in ring theory, as they encode significant information about the underlying algebraic structure. In this paper, we study idempotent matrices from two perspectives. First, we analyze the partially…

Rings and Algebras · Mathematics 2025-10-13 Sen-Peng Eu , Yong-Siang Lin , Wei-Liang Sun

A commutator of unipotent matrices of index 2 is a matrix of the form $XYX^{-1}Y^{-1}$, where $X$ and $Y$ are unipotent matrices of index 2, that is, $X\ne I_n$, $Y\ne I_n$, and $(X-I_n)^2=(Y-I_n)^2=0_n$. If $n>2$ and $\mathbb F$ is a field…

Rings and Algebras · Mathematics 2024-09-23 Kennett L. Dela Rosa , Juan Paolo C. Santos

In this paper, we study the non trivial idempotents of the $2 \times 2$ matrix ring over the polynomial ring $\mathbb{Z}_{pqr}[x]$ for distinct primes $p, q $ and $r$ greater than $3$. We have classified all the idempotents of this matrix…

Rings and Algebras · Mathematics 2020-11-17 Gaurav Mittal

In this paper we give a purely categorical construction of d-fold matrix factorizations of a natural transformation, for any even integer d. This recovers the classical definition of those for regular elements in commutative rings due to…

K-Theory and Homology · Mathematics 2023-08-30 Petter Andreas Bergh , David A. Jorgensen

The paper studies algebraic strong shift equivalence of matrices over $n$-variable polynomial rings over a principal ideal domain $D$($n\leq 2$). It is proved that in the case $n=1$, every non-zero matrix over $D[x]$ has a full rank…

Rings and Algebras · Mathematics 2007-10-23 Sheng Chen

We study the class of those linear relations that can be factorized as products of idempotent relations. We provide several characterizations of this class, extending known factorization results for operators to the more general setting of…

Functional Analysis · Mathematics 2025-06-13 M. Laura Arias , Maximiliano Contino , Stefania Marcantognini

A unimodular $2\times 2$ matrix with entries in a commutative $R$ is called extendable (resp.\ simply extendable) if it extends to an invertible $3\times 3$ matrix (resp.\ invertible $3\times 3$ matrix whose $(3,3)$ entry is $0$). We obtain…

Commutative Algebra · Mathematics 2025-07-28 Grigore Călugăreanu , Horia F. Pop , Adrian Vasiu

Let $R$ be a commutative unital ring. A well-known factorization problem is whether any matrix in $\mathrm{SL}_n(R)$ is a product of elementary matrices with entries in $R$. To solve the problem, we use two approaches based on the notion of…

Commutative Algebra · Mathematics 2019-02-12 Evgueni Doubtsov , Frank Kutzschebauch

We investigate invertible matrices over finite additively idempotent semirings. The main result provides a criterion for the invertibility of such matrices. We also give a construction of the inverse matrix and a formula for the number of…

Rings and Algebras · Mathematics 2012-08-13 Andreas Kendziorra , Stefan E. Schmidt , Jens Zumbrägel

For the integer $ D=pq$ of the product of two distinct odd primes, we construct an elliptic curve $E_{2rD}:y^2=x^3-2rDx$ over $\mathbb Q$, where $r$ is a parameter dependent on the classes of $p$ and $q$ modulo 8, and show, under the parity…

Number Theory · Mathematics 2015-03-13 Xiumei Li , Jinxiang Zeng

Let F be a finite field and R = M2(F) be 2x2 matrix ring over F. In this paper, we explicitly determine all the idempotents in R. Using these idempotents, we study the idempotent graph of R whose vertex set is the set of non-trivial…

Combinatorics · Mathematics 2024-02-20 Avinash Patil , P. S. Momale , C. M. Jadhav

We investigate the problem asking when any square matrix whose entries lie in a finite field of characteristic 2 is decomposable into the sum of a diagonalizable matrix and a nilpotent matrix with index of nilpotency at most 2 and, as a…

Rings and Algebras · Mathematics 2026-04-17 Peter Danchev , Esther García , Miguel Gómez Lozano

We show that every integer doubly nonnegative $2 \times 2$ matrix has an integer cp-factorization.

Optimization and Control · Mathematics 2018-02-13 Thomas Laffey , Helena Šmigoc
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