摘要:

We investigate the concept of dominion (in the sense of Isbell) in several varieties of nilpotent groups. We obtain a complete description of dominions in the variety of nilpotent groups of class at most two. Then we look at the behavior of dominions of subgroups of groups inN2when taken in the context ofNcforc>2. Finally, we establish the existence of nontrivial dominions in the category of all nilpotent groups.

ISSN:0092-7872    

DOI:10.1080/00927870008826892

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

摘要:

Here we initiate an investigation into the classeOof extended Ockham algebras, namely bounded distributive lattices endowed with a commuting pair of unary operations, one of which is an endomorphism and the other is a dual endomorphism. A consideration of the subdirectly irreducible algebras leads, via Priestley duality, to a description of all finite subdirectly irreducibleeO-algebras. In particular, we show that there are precisely nine non-isomorphic subdirectly irreducible symmetric extended de Morgan algebras, all of which are simple. We also describe the corresponding lattice of varieties.

ISSN:0092-7872    

DOI:10.1080/00927870008826893

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927870008826894

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

摘要:

A sharp bound is derived for the nilpotency class of a regularp-group in terms of its coexponent, and is used to show that the number of groups of orderpnwith a given fixed coexponent, is independent ofn, forpandnsufficiently large. Explicit formulae are calculated in the case of coexponent 3.

ISSN:0092-7872    

DOI:10.1080/00927870008826895

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927870008826896

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

摘要:

We consider the question of whether anFC-groupGin which the derived subgroup [G, G] is a subgroup of a direct product of finite groups must have its central factor groupG/Z(G) also embeddable in a direct product of finite groups.

ISSN:0092-7872    

DOI:10.1080/00927870008826897

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927870008826898

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927870008826899

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

摘要:

In this paper we consider homogeneous Gorenstein ideals of codimension three in a polynomial ring and determine their graded Betti numbers in terms of their Hilbert function. For such ideals we prove also a lifting theorem in the vein of a classical result of Hartshorne concerning monomial ideals.

ISSN:0092-7872    

DOI:10.1080/00927870008826900

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

摘要:

In this paper we study the category of finitely generated modules of finite projective dimension over a class of weakly triangular algebras, which includes the algebras whose idempotent ideals have finite projective dimension. In particular, we prove that the relations given by the (relative) almost split sequences generate the group of all relations for the Grothendieck group ofP<∞(Λ) if and only ifP<∞(Λ) is of finite type. A similar statement is known to hold for the category of all finitely generated modules over an artin algebra, and was proven by C.M.Butler and M. Auslander ( [B] and [A]).

ISSN:0092-7872    

DOI:10.1080/00927870008826901

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor