scholarly journals Elements in exchange rings with related comparability

2000 ◽  
Vol 23 (9) ◽  
pp. 639-644 ◽  
Author(s):  
Huanyin Chen

We show that ifRis an exchange ring, then the following are equivalent: (1)Rsatisfies related comparability. (2) Givena,b,d∈RwithaR+bR=dR, there exists a related unitw∈Rsuch thata+bt=dw. (3) Givena,b∈RwithaR=bR, there exists a related unitw∈Rsuch thata=bw. Moreover, we investigate the dual problems for rings which are quasi-injective as right modules.

2004 ◽  
Vol 03 (02) ◽  
pp. 207-217 ◽  
Author(s):  
HUANYIN CHEN

In this paper, we investigate the necessary and sufficient conditions on exchange rings, under which every regular matrix admits diagonal reduction. Also we show that an exchange ring R is strongly separative if and only if for any finitely generated projective right R-module C, if A and B are any right R-modules such that 2C⊕A≅C⊕B, then C⊕A≅B.


2010 ◽  
Vol 17 (01) ◽  
pp. 87-100 ◽  
Author(s):  
Huanyin Chen

In this article, we investigate new necessary and sufficient conditions on an exchange ring under which every regular matrix admits a diagonal reduction. We prove that an exchange ring R is an hermitian ring if and only if for any n ≥ 2 and any regular x ∈ Rn, there exists u ∈ CLn(R) such that x = xux; if and only if for any n ≥ 2 and any regular x ∈ Rn, there exists u ∈ CLn(R) such that xu ∈ R is an idempotent. Furthermore, we characterize such exchange rings by means of reflexive inverses and n-pseudo-similarity.


2001 ◽  
Vol 25 (12) ◽  
pp. 763-770 ◽  
Author(s):  
Huanyin Chen

We investigate the sufficient conditions and the necessary conditions on an exchange ringRunder whichRhas stable range one. These give nontrivial generalizations of Theorem 3 of V. P. Camillo and H.-P. Yu (1995), Theorem 4.19 of K. R. Goodearl (1979, 1991), Theorem 2 of R. E. Hartwig (1982), and Theorem 9 of H.-P. Yu (1995).


2008 ◽  
Vol 50 (3) ◽  
pp. 509-522 ◽  
Author(s):  
TSIU-KWEN LEE ◽  
YIQIANG ZHOU

AbstractIt is well known that a ring R is an exchange ring iff, for any a ∈ R, a−e ∈ (a2−a)R for some e2 = e ∈ R iff, for any a ∈ R, a−e ∈ R(a2−a) for some e2 = e ∈ R. The paper is devoted to a study of the rings R satisfying the condition that for each a ∈ R, a−e ∈ (a2−a)R for a unique e2 = e ∈ R. This condition is not left–right symmetric. The uniquely clean rings discussed in (W. K. Nicholson and Y. Zhou, Rings in which elements are uniquely the sum of an idempotent and a unit, Glasgow Math. J. 46 (2004), 227–236) satisfy this condition. These rings are characterized as the semi-boolean rings with a restricted commutativity for idempotents, where a ring R is semi-boolean iff R/J(R) is boolean and idempotents lift modulo J(R) (or equivalently, R is an exchange ring for which any non-zero idempotent is not the sum of two units). Various basic properties of these rings are developed, and a number of illustrative examples are given.


2015 ◽  
Vol 14 (07) ◽  
pp. 1550101
Author(s):  
Alin Stancu

In this paper, we discuss several constructions that lead to new examples of nil-clean, clean and exchange rings. Extensions by ideals contained in the Jacobson radical is the common theme of these constructions. A characterization of the idempotents in the algebra defined by a 2-cocycle is given and used to prove some of the algebra's properties (the infinitesimal deformation case). From infinitesimal deformations, we go to full deformations and prove that any formal deformation of a clean (exchange) ring is itself clean (exchange). Examples of nil-clean, clean and exchange rings, arising from poset algebras are also discussed.


2008 ◽  
Vol 15 (02) ◽  
pp. 193-198 ◽  
Author(s):  
Huanyin Chen

A ring R is said to be a generalized stable ring provided that aR + bR = R with a, b ∈ R implies that there exists y ∈ R such that a + by ∈ K(R), where K(R) = {x ∈ R | ∃s, t ∈ R such that sxt = 1}. Let A be a quasi-projective right R-module, and let E = End R(A). If E is an exchange ring, then E is a generalized stable ring if and only if for any R-morphism f : A → M with Im f ≤⊕M and any R-epimorphism g : A → M, there exist e = e2 ∈ E and h ∈ K(E) such that f = g(eh). Furthermore, we prove that every regular matrix over a generalized stable exchange ring admits a diagonal reduction by quasi-invertible matrices.


1999 ◽  
Vol 27 (9) ◽  
pp. 4209-4216 ◽  
Author(s):  
Huanyin Chen

2009 ◽  
Vol 08 (05) ◽  
pp. 629-632
Author(s):  
GRIGORE CĂLUGĂREANU

A direct ring-theoretic proof for "if R is a ring, e is an idempotent and eRe and (1 - e)R(1 - e) are both exchange rings then R is also an exchange ring" (left open for the last 31 years) is given.


2001 ◽  
Vol 26 (7) ◽  
pp. 393-398 ◽  
Author(s):  
Huanyin Chen ◽  
Fu-an Li

We show that ifRis an exchange ring with primitive factors artinian thenK1(R)≅U(R)/V(R), whereU(R)is the group of units ofRandV(R)is the subgroup generated by{(1+ab)(1+ba)−1|a,b∈R   with   1+ab∈U(R)}. As a corollary,K1(R)is the abelianized group of units ofRif1/2∈R.


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