摘要:

In the present paper, we study varieties consisting of bands (idempotent semigroups) endowed with an involutorial antiautomorphism * as a fundamental operation. Our principal aim is here to provide an insight to some classes of these varieties from the structural point of view, especially in terms of semilattice decompositions, subdirect products and ideal extensions. In the course of such considerations, we shall extend the result of C. L. Adair [1], who described the lattice of all varieties of bands with a regular involution (i.e. with the identityx=xx*x) We depict a broader lattice of involution band varieties, which incorporates Adair’s lattice.

ISSN:0092-7872    

DOI:10.1080/00927870008826995

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

摘要:

LetVKbe a twisted form of P3over the function field of an algebraic surface with PicVKgenerated by the half of the canonical line bundle. We construct an algebraic fibre spaceV→Xprojective flat over a smooth projective surfaceXwith the generic fibreVK→ SpacKsatisfying some properties.

ISSN:0092-7872    

DOI:10.1080/00927870008826996

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

摘要:

The notion of a large set in an arbitrary group is introduced in analogy to the generic sets in an algebraic or stable group. The question is studied which properties “satisfied largely” by a group hold on the entire group.

ISSN:0092-7872    

DOI:10.1080/00927870008826997

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

摘要:

A Lie subalgebraLof glk(V) is said to befinitaryif it consists of elements of finite rank. We show that every simple finitary Lie algebra over a field of characteristic ≠2, 3, 5, 7 has a local system consisting of perfect central extensions of finite-dimensional simple Lie algebras.

ISSN:0092-7872    

DOI:10.1080/00927870008826998

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

摘要:

For al large class of endomorphisms of finitely generated free groups we prove that their mapping tori groups are word-hyperbolic if and only if they don’t contain Baumslag-Solitar subgroups.

ISSN:0092-7872    

DOI:10.1080/00927870008826999

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927870008827000

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927870008827001

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

摘要:

We give a complete classification of the 32-dimensional pointed Hopf algebras over an algebraically closed field k with chark k ≠ 2. It turns out that there are infinite families of isomorphism classes of pointed Hopf algebras of dimension 32. In [AS1], [BDG] and [Ge] are given families of counterexamples for the tenth Kaplansky conjecture. Up to now, 32 is the lowest dimension where Kaplansky conjecture fails.

ISSN:0092-7872    

DOI:10.1080/00927870008827002

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

摘要:

For any integersn>m≥ 2, we say that a complete theoryTis (m, n)-homogeneous if, for each modelMofT, two n-tuples ⱥ,ƀ inMhave the same type if the corresponding m-tuples from ⱥ and ƀ have the same type. It was conjectured by H. Kikyo that, ifMis an infinite group, with possibly additional structure, then the theory ofMis not (m, n)-homogeneous. We prove a general result on structures with (m, n)-homogeneous theory which implies that, ifMis a counterexample to this conjecture, then there exists an integerhsuch that each abelian subgroup ofMhas at mosthelements. It follows that there exist an integerksuch thatMk= 1, and an integerlsuch that each finite subgroup ofMhas at mostlelements.

ISSN:0092-7872    

DOI:10.1080/00927870008827003

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927870008827004

出版商:Gordon and Breach Science Publishers Ltd.    

年代:2000

数据来源: Taylor