On the torsion units of the integral group ring of finite projective special linear groups

H. J. Zassenhaus conjectured that any unit of finite-order and augmentation one in the integral group ring of a finite group G is conjugate in the rational group algebra to an element of G. One way to verify this is showing that such unit has the same distribution of partial augmentations as an element of G and the HeLP Method provides a tool to do that in some cases. In this paper, we use the HeLP Method to describe the partial augmentations of a hypothetical counterexample to the conjecture for the projective special linear groups.     

A primitive ring which is a sum of two Wedderburn radical subrings

We give an example of a primitive ring which is a sum of two Wedderburn radical subrings. This answers an open question and simplifies the proof of the known theorem that there exists a ring which is not nil but is a sum of two locally nilpotent subrings.

     

On the completeness of factor rings

Let be a complete local domain containing the integers with maximal ideal such that is at least the cardinality of the real numbers. Let be a nonmaximal prime ideal of such that is a regular local ring. We construct an excellent local ring such that the completion of is , the generic formal fiber of is local with maximal ideal and if is a nonzero ideal of , then is complete.

     

The radical-annihilator monoid of a ring

Kuratowski’s closure-complement problem gives rise to a monoid generated by the closure and complement operations. Consideration of this monoid yielded an interesting classification of topological spaces, and subsequent decades saw further exploration using other set operations. This article is an exploration of a natural analogue in ring theory: a monoid produced by “radical” and “annihilator” maps on the set of ideals of a ring. We succeed in characterizing semiprime rings and commutative dual rings by their radical-annihilator monoids, and we determine the monoids for commutative local zero-dimensional (in the sense of Krull dimension) rings.     

Steenrod operations on the Chow ring of a classifying space

We use the Steenrod algebra to study the Chow ring CH^*BG of the classifying space of an algebraic group G. We describe a localization property which relates a given G to its elementary abelian subgroups, and we study a number of particular cases, namely symmetric groups and Chevalley groups. It turns out that the Chow rings of these groups are completely determined by the abelian subgroups and their fusion.     

On the hopficity of the polynomial rings

In this paper we prove that if a ringR satisfies the condition that for some integern > 1,a ⁿ =a for everya inR, thenR a hopfian ring implies that the ringR [T] of polynomials is also hopfian. This generalizes a recent result of Varadarajan which states that ifR is a Boolean hopfian ring then the ringR[T] is also hopfian. We show furthermore that there are numerous ringsR satisfying the hypothesis of our theorem which are neither Boolean nor Noetherian.     

关于内射模的P-平坦性

通过引用P-平坦模的定义,引入了右IPF环的概念,推广了右IF环的概念,这对研究IF环及QF环具有重要的作用,同时对右IPF环的性质作了一些刻画,得到了右IPF环的若干个等价命题;最后,用P-平坦模及右IPF环推出了正则环的一些等价条件．     

The ideal of polynomials vanishing on a commutative ring

We determine equivalent conditions on a commutative Artinian ring in order that the ideal of consisting of polynomials that vanish on should be principal. Our results correct an error in a paper of Niven and Warren.

     

关于凝聚局部环的正则性

本文证明了极大理想m是有限生成的交换凝聚局部环（R,M）是正则的充分必要条件是m可以由一个正则R-序列生成,推广了文献[1]中相应的结论并给出了一个由正则凝聚局部环构造大量的非正则凝聚局部环的方法．     

On the equations defining monomial curves

Let C be a monomial curve in three dimensional projective space over an algebraically closed field K of characteristic zero . We give several necessary criterions for C to be set theoretic complete intersection. Using these criterions we get several restrictions concerning the form of the equations that define C set theoretically.     

On the upper radical determined by filial rings

Summary Filial rings are rings in which the relation of being an ideal is transitive. The upper radical determined by the class of such rings is studied. Several known results are extended and some open problems are answered.     

Automorphisms of the standard Borel subalgebra of Lie algebra of Cm type over a commutative ring

All automorphisms of the standard Borel subalgebra of the symplectic algebra sp(2m,?R) are determined, provided that R is a commutative ring with identity, 2 is invertible in R.     

G-分次环与G-集的Smash积和Morita Context

设R是G-分次环，A是G-集，（H,B)的忠实子对象，本文讨论了分次模范畴（A，R)-gr与分次模范范畴（B，Rn）-gr等价的条件；给出了R#A是单环，R#G／H是素环的刻划，所得结果均推广了已有结论。     

Faltings' theorem for the annihilation of local cohomology modules over a Gorenstein ring

In this paper we study the Annihilator Theorem and the Local-global Principle for the annihilation of local cohomology modules over a (not necessarily finite-dimensional) Noetherian Gorenstein ring.