On Matrix Rings and Subhereditary Radicals

Abstract

We study some one-sided ideals of row bounded and of column bounded matrix rings over free algebras. Obtained results are applied to answer several open problems on subhereditary radicals of associative rings. In particular we show that the right strongly prime radical is not left subhereditary and that the lattice of left (right) subhereditary radicals is not complete.     

On Principally Left Strong Radicals

Principally left strong radicals were introduced in [4]. Here, we continue to study such radicals. Principally left strong radicals and their semisimple classes are characterized in Section 2. Sections 3 and 4 are devoted to the lower principally left strong radical construction and to the upper principally left strong radical construction, respectively. This revised version was published online in June 2006 with corrections to the Cover Date.     

Lattices of Radicals of Involution Rings

A lattice-theoretic approach to the radical theory of rings was initiated by Snider. In the current paper, we extend this approach to the radical theory of involution rings. We show that the classes of hereditary radicals, radicals satisfying ADS and invariant radicals form complete sublattices of the lattice of all radicals of involution rings. We show that certain sublattices are isomorphic to sublattices of the lattice of radicals of rings. We characterize the atoms of certain lattices of radicals of involution rings.1991 Mathematics Subject Classification: 16W10, 16N99, 06B99     

On Extensions of Chain Algebras and Atoms of the Lattice of Radicals

In this article we study the problem when a left distributive algebra over a field determines an atom of the lattice of all radicals of rings. We show that this problem is strictly connected with the problem of describing extensions of left chain algebras and give a characterization of left chain algebras determining atoms.     

Hereditary Upper Radical Properties and Dual Supplementing Radicals of Hereditary Radicals of Groups

One aim of this paper is to prove that for any hereditary radical property 𝒫, there exists a radical property 𝒫′ supplementing 𝒫. Certain hereditary upper radical properties of groups are constructed, and some of them are applied to formulate the necessary and sufficient condition for a hereditary radical 𝒫 and its supplementing radical 𝒫′ forming a dual pair.     

关于MHR环的根

本文证明了对ＭＨＲ环来说，Ｂｅａｒ根与有极小右理想的单环类决定的上根Ｕ在强意义之下是一致的，以及Ｕ根与Ｚ根在弱意义之下是一致的。推广了文「１」中对ＭＨＲ环来说，Ｂｅａｒ根与Ｊａｃｈｏｂｓｏｎ根在强意义之下是一致的，以及Ｊａｃｏｂｓｏｎ根与Ｚ根在弱意义之下一致的结果。     

一类二阶非线性发展方程整体解的渐近性

本文应用一个差分不等式证明了一类二阶非线性发展方程初边值问题整体解的衰减性质.     

A linear algebra approach to Koethe's problem and related questions

We discuss several problems on the structure of nil rings from the linear algebra point of view. Among others, a number of questions and results are presented concerning algebras of infinite matrices over nil algebras, and nil algebras of infinite matrices over fields, which are related to the famous Koethe's problem. Some questions on radicals of tensor products of algebras related to Koethe's problem are also discussed.     

关于序半群理想的根

Let S be an ordered semigroup.In this paper,we characterize ordered semigroups in which the radical of every ideal（right ideal,bi-ideal） is an ordered subsemigroup（resp.,ideal,right ideal,left ideal,bi-ideal,interior ideal） by using some binary relations on S.     

An Ascending Chain Condition on Wedderburn Radicals

In this note we study the properties of Amitsur's example for Wedderburn radicals, introducing the concept of W _n -reduced rings. The theories of commutative ring and reduced ring are generalized to W _n -reduced rings. We characterize the W _n -reduced property and study properties of W _n -reduced rings. It is shown that the classes of semi-commutative rings, W _n -reduced rings, and 2-primal rings are in a strictly increasing order. We extend the class of W _n -reduced rings, observing various kinds of extensions containing classical quotient rings, polynomial rings, and power series rings.

Communicated by M. Ferrero.     

关于相对紧性质的研究

利用有限交性质的集族及网的性质描述了相对紧性质,给出了相对紧性质的两个等价结果.     

正则环的投射根

研究了正则环上投射根的性质.证明了正则环的投射根左右对称,且模去投射根的正则环只有零投射根.给出了矩阵环及角落环投射根的计算式,并得到了投射根为零的正则环的一些刻画。最后讨论了投射根为零的正则环在各种环运算下的封闭性和正则环的MP-维数.     

Topologically Irreducible Representations and Radicals in Banach Algebras

It is shown that the topologically irreducible representationsof a normed algebra define a certain topological radical inthe same way that the strictly irreducible representations definethe Jacobson radical and that this radical can be strictly smallerthan the Jacobson radical. An abstract theory of ‘topologicalradicals’ in topological algebras is developed and usedto relate this radical to the Baer radical (prime radical).The relations with topologically transitive representationsand standard representations in the sense of Meyer are alsoexplored. 1991 Mathematics Subject Classification: 46H15, 46H25,16Nxx.     

模自同态环的理想格与正规根

设_RＰ是环Ｒ上的左模．记P^*= Hom _R(P , R ) , J = P P^*, S₀= P^*P．本文讨论了Ｊ与Ｓ的双零化理想格之间的关系，以及Ｒ，Ｊ，Ｓ₀和Ｅｎｄ_RＰ的正规根之间的关系．     

On Banach spaces with Kasparov and Yu's Property (H)

A new geometric property of Banach spaces recently introduced by G. Kasparov and G. Yu, called Property (H), has important applications to the strong Novikov conjecture and the coarse Novikov conjecture, yet is far from being well understood. In this paper, we investigate various uniformly continuous maps on unit spheres of Banach spaces and prove that all separable Banach lattices with nontrivial cotype have Property (H).     

On the shape of a convex body with respect to its second projection body

We prove results relative to the problem of finding sharp bounds for the affine invariant $P(K)=V(\mathrm{\Pi }K)/V^{d-1}(K)$. Namely, we prove that if K is a 3-dimensional zonoid of volume 1, then its second projection body ${\mathrm{\Pi }}^{2}K$ is contained in 8K, while if K is any symmetric 3-dimensional convex body of volume 1, then ${\mathrm{\Pi }}^{2}K$ contains 6K. Both inclusions are sharp. Consequences of these results include a stronger version of a reverse isoperimetric inequality for 3-dimensional zonoids established by the author in a previous work, a reduction for the 3-dimensional Petty conjecture to another isoperimetric problem and the best known lower bound up to date for $P(K)$ in 3 dimensions. As byproduct of our methods, we establish an almost optimal lower bound for high-dimensional bodies of revolution.     

具有性质$b_1$空间的乘积性

In this note,we present that:(1)Let X=σ{Xα:α∈A} be|A|-paracompact (resp.,hereditarily |A|-paracompact).If every finite subproduct of {Xα:α∈A} has property b1 (resp.,hereditarily property b1),then so is X.(2) Let X be a P-space and Y a metric space.Then,X×Y has property b1 iff X has property b1.(3) Let X be a strongly zero-dimensional and compact space.Then,X×Y has property b1 iff Y has property b1.