摘要:

LetU=U(sl2)⊗nbe the tensor power of n copies of the enveloping algebraU(sl2) over an arbitrary fieldKof characteristic zero. In this paper we list the prime ideals ofUby generators and classify them by height. IfZis the center ofUandJis a prime ideal ofZ, there are exactly 25prime idealsIofUwithI∩Z=J, where 0 ≤ s = s(J) ≤ n is an integer. Indeed, with respect to inclusion, they form a lattice isornorphic to the lattice of subsets of a set. WhenJis a maximal ideal ofZ, there are only finitely many two-sided ideals ofUcontainingJ, They are presented by generators and their lattice is described, In particular, for each suchJthere exists a unique maximal ideal ofUcontainingJand a unique ideal ofUminimal with respect to the property that it properly containsJU. Similar results are given in the case whenUis the tensor product of infinitely many copies ofU(sl2).

ISSN:0092-7872    

DOI:10.1080/00927879908826761

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

摘要:

LetSbe a semigroup of words over an alphabet ∑ . Suppose tliar every two wordsuand e over ∑ are equal inSif (1) the sets of subwords of lengthkof the wordsaandbcoincide and are non-empty. (2) the prefix (suffix) ofuof lengthk1 is equal to the prefix (suffix) of e. ThenSis called k-testable. A semigroup is locally testable if it isk-testable for somek> 0.

ISSN:0092-7872    

DOI:10.1080/00927879908826762

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

摘要:

The varietydpk1,1consists of those algebras (L;⋁,⋀,f,*,0,1) of type (2,2,1,1,0,0) where (L;⋁,⋀,f,0,1) is an Ockham algebra in whichf3=f, (L;⋁,⋀,*,0,1) is a demi-pseudocomplemented lattice, and the unary operationsfand*commute. Here we give a description of the structure of the lattice of congruences of a subdirectly irreducible algebra indpk1,1.

ISSN:0092-7872    

DOI:10.1080/00927879908826763

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

摘要:

The varietypOconsists of those algebras (L;⋁,⋀,f,*,0,1) where (L;⋁,⋀,f,0,1) is an Ockham algebra, (L;⋁,⋀,f,*,0,1) is ap-algebra, and the unary operationsfand*. commute. For an algebra inpKωwe show that the compact congruences form a dual Stone lattice and use this to determine necessary and sufficient conditions for a principal congruence to be complemented. We also describe the lattice of subvarieties ofpK1,1identifying therein the biggest subvariety in which every principal congruence is complemented, and the biggest subvariety in which the intersection of two principal congruences is principal.

ISSN:0092-7872    

DOI:10.1080/00927879908826764

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

摘要:

LetGLn=GL(n,Fp) be the group of alln×ninvertible matrices over the fieldFpof p elements, p a prime number. As well known, a complete set of irreducibleGLn-modules as submodules of the polynomial algebra was constructed by Stephen Doty and Grant Walker, Ton That Tri (see [1], [4]). Grant Walker has a conjecture that the occurence of these modules is the first occurence of these modules as submodules in the polynomial algebra. The aim of this paper is to give a proof of the above conjecture forp= 2.

ISSN:0092-7872    

DOI:10.1080/00927879908826765

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

摘要:

A congruence ρTon a subsemigroupTofSextends to the semigroupS, if there exists a congruence ρ onSsuch that the restriction ρ |Tof ρ onTis ρT. A semigroupShas the congruence extension property, CEP, if each congruence on each subsemigroup extends toS.

ISSN:0092-7872    

DOI:10.1080/00927879908826766

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927879908826767

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927879908826768

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

摘要:

We classify completely all quasi-complete intersections of monomial curves inKan infinite field, see Theorem 4.1 and Theorem 4.2. This completes the investigations started in [4].

ISSN:0092-7872    

DOI:10.1080/00927879908826769

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

摘要:

In this paper we carry out a systematic study of various ring theoretic properties of formal triangular matrix rings. Some definitive results are obtained on these rings concerning properties such as being respectively left Kasch, right mininjective, clean, potent, right PF or a ring of stable rank ≤n. The concepts of a strong left Kasch ring, a strong right mininjective ring are introduced and it is determined when the triangular matrix rings are respectively strong left Kasch or strong right mininjective. It is also proved that being strong left Kasch or strong right mininjective are Morita invariant properties.

ISSN:0092-7872    

DOI:10.1080/00927879908826770

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor