ISSN:0092-7872    

DOI:10.1080/00927878908823838

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1989

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927878908823839

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1989

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927878908823840

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1989

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927878908823841

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1989

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927878908823842

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1989

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927878908823843

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1989

数据来源: Taylor

摘要:

We define the relative Tits form number W(G, V) of a valued bigraph G at a vertex v and derive some basic properties. We give a detailed analysis of the case when W (G,V) ≥½. The properties of these numbers were used without proof in the classification of Auslander algebras of finite representation type [IPTZ]

ISSN:0092-7872    

DOI:10.1080/00927878908823844

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1989

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927878908823845

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1989

数据来源: Taylor

摘要:

Herrlich, Salicrup, and Strecker [HSS] have shown that Kuratowski’s Theorem, namely, that a space X is compact if and only if for every space Y, the projection π2X×Y → Y is a closed map, can be interpreted categorically, and hence generalized and applied in a wider settin than the category of topological spaces. The first author, in an earlier paperj [Fl] , applied this categorical interpretation of compactness in categories of R-modules, obtaining a theory of compactness for each torsion theory T. In the case of the category of abelian groups and a hereditary torsion theory T, a group G is T-compact provided G/TG is a T-injective. In this note, the notion of compact is extended to the categories of hypercentral groups, nilpotent groups, and of FC-groups; it is shown that ifTπdenotes the π-torsion subgroup functor for a set of primes π, then a group G isTπ-compact provided G/TπG is π-complete, extending the abelian group result in a natural way.

ISSN:0092-7872    

DOI:10.1080/00927878908823846

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1989

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927878908823847

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1989

数据来源: Taylor