scholarly journals TWO QUESTIONS OF L. VAŠ ON -CLEAN RINGS

2013 ◽  
Vol 88 (3) ◽  
pp. 499-505 ◽  
Author(s):  
JIANLONG CHEN ◽  
JIAN CUI

AbstractA $\ast $-ring $R$ is called (strongly) $\ast $-clean if every element of $R$ is the sum of a unit and a projection (that commute). Vaš [‘$\ast $-Clean rings; some clean and almost clean Baer $\ast $-rings and von Neumann algebras’, J. Algebra 324(12) (2010), 3388–3400] asked whether there exists a $\ast $-ring that is clean but not $\ast $-clean and whether a unit regular and $\ast $-regular ring is strongly $\ast $-clean. In this paper, we answer these two questions. We also give some characterisations related to $\ast $-regular rings.

Author(s):  
Zoran Petrovic ◽  
Maja Roslavcev

Let R be a commutative von Neumann regular ring. We show that every finitely generated ideal I in the ring of polynomials R[X] has a strong Gr?bner basis. We prove this result using only the defining property of a von Neumann regular ring.


1985 ◽  
Vol 37 (6) ◽  
pp. 1134-1148
Author(s):  
David Handelman

In this paper, we are primarily concerned with the behaviour of the centre with respect to the completion process for von Neumann regular rings at the pseudo-metric topology induced by a pseudo-rank function.Let R be a (von Neumann) regular ring, and N a pseudo-rank function (all terms left undefined here may be found in [6]). Then N induces a pseudo-metric topology on R, and the completion of R at this pseudo-metric, , is a right and left self-injective regular ring. Let Z( ) denote the centre of whatever ring is in the brackets. We are interested in the map .If R is simple, Z(R) is a field, so is discrete in the topology; yet Goodearl has constructed an example with Z(R) = R and Z(R) = C [5, 2.10]. There is thus no hope of a general density result.


1974 ◽  
Vol 17 (2) ◽  
pp. 283-284 ◽  
Author(s):  
Kwangil Koh

Recently, in the Research Problems of Canadian Mathematical Bulletin, Vol. 14, No. 4, 1971, there appeared a problem which asks “Is a prime Von Neumann regular ring pimitive?” While we are not able to settle this question one way or the other, we prove that in a Von Neumann regular ring, there is a maximal annihilator right ideal if and only if there is a minimal right ideal.


Author(s):  
Najib Mahdou

We show that eachR-module isn-flat (resp., weaklyn-flat) if and only ifRis an(n,n−1)-ring (resp., a weakly(n,n−1)-ring). We also give a new characterization ofn-Von Neumann regular rings and a characterization of weakn-Von Neumann regular rings for (CH)-rings and for local rings. Finally, we show that in a class of principal rings and a class of local Gaussian rings, a weakn-Von Neumann regular ring is a (CH)-ring.


1971 ◽  
Vol 4 (1) ◽  
pp. 57-62 ◽  
Author(s):  
K. M. Rangaswamy ◽  
N. Vanaja

It is shown that a von Neumann regular ring R is left seif-injective if and only if every finitely generated torsion-free left R-module is projective. It is further shown that a countable self-injective strongly regular ring is Artin semi-simple.


2013 ◽  
Vol 20 (02) ◽  
pp. 343-347 ◽  
Author(s):  
Liang Shen

Let R be a J-regular ring, i.e., R/J(R) is a von Neumann regular ring, where J(R) is the Jacobson radical of R. It is proved: (i) For every n ≥ 1, R is right n-injective if and only if every homomorphism from an n-generated small right ideal of R to RR can be extended to one from RR to RR. (ii) R is right FP-injective if and only if R is right (J,R)-FP-injective. Some known results are improved.


1969 ◽  
Vol 12 (4) ◽  
pp. 417-426 ◽  
Author(s):  
R.C. Courter

We prove in this paper that fifteen classes of rings coincide with the class of rings named in the title. One of them is the class of rings R such that X2 = X for each R-ideal X: we shall refer to rings with this property (and thus to the rings of the title) as fully idempotent rings. The simple rings and the (von Neumann) regular rings are fully idempotent. Indeed, every finitely generated right or left ideal of a regular ring is generated by an idempotent [l, p. 42], so that X2 = X holds for every one-sided ideal X.


2011 ◽  
Vol 10 (06) ◽  
pp. 1363-1370 ◽  
Author(s):  
CHUNNA LI ◽  
YIQIANG ZHOU

A *-ring R is called a *-clean ring if every element of R is the sum of a unit and a projection, and R is called a strongly *-clean ring if every element of R is the sum of a unit and a projection that commute with each other. These concepts were introduced and discussed recently by [L. Vaš, *-Clean rings; some clean and almost clean Baer *-rings and von Neumann algebras, J. Algebra324 (2010) 3388–3400]. Here it is proved that a *-ring R is strongly *-clean if and only if R is an abelian, *-clean ring if and only if R is a clean ring such that every idempotent is a projection. As consequences, various examples of strongly *-clean rings are constructed and, in particular, two questions raised in [L. Vaš, *-Clean rings; some clean and almost clean Baer *-rings and von Neumann algebras, J. Algebra324 (2010) 3388–3400] are answered.


2016 ◽  
Vol 26 (06) ◽  
pp. 1177-1198 ◽  
Author(s):  
Dinesh Khurana ◽  
T. Y. Lam ◽  
Pace P. Nielsen

In this paper, we study exchange rings and clean rings [Formula: see text] with [Formula: see text] (or otherwise). Analogues of a theorem of Camillo and Yu characterizing clean and strongly clean rings with [Formula: see text] are obtained for such rings (as well as for exchange rings) using the viewpoint of exchange equations introduced in a recent paper of the authors. We also study a new class of rings including von Neumann regular rings in which square roots of one (instead of idempotents) can be lifted modulo left ideals, and conjecture that such rings are exchange rings. This conjecture holds for commutative rings, and would hold for all rings if it holds for semiprimitive rings of characteristic [Formula: see text].


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