摘要:

Let;Kbe the Kronecker algebra;MaK-indecomposable;C(K) the composition algebra ofK. By using the triangular decomposition ofC(K) we prove that [M] ∈C(K) if and only ifMis either a preprojective or a preinjective.

ISSN:0092-7872    

DOI:10.1080/00927879908826720

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927879908826721

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927879908826722

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

摘要:

We study the process of resolution of linear systems on 2-dimensional regular local rings by quadratic transformations and we give an effective characterization of the Zariski open set of equisingular elements in the linear system. We give a description of the behaviour at the first infinitesimal neighborhood by means of the Plücker Formulas.

ISSN:0092-7872    

DOI:10.1080/00927879908826723

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

摘要:

Let S be the numerical semigroup generated by, where the siare positive integers with. Let I be a relative ideal of S Then the dual of I is. Let μ· denote the size of a minimal generating set. A question motivated by the study of torsion in tensor products is under what conditions on S and I do we have the strict inequality μ(I + (S – I)) < μ(I)μ(S –I) Specifically, what is the smallest multiplicity of S, that is, the smallest value of s1for which equality can hold for some non-principal relative ideal I. We will examine this question in the case μ(I) = μ(S – I) = 2 and see that the smallest multiplicity is ten.

ISSN:0092-7872    

DOI:10.1080/00927879908826724

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

摘要:

A theorem of Karrass, Pietrowski and Solitar on the structure of the automorphism group of an amalgamated free product is extended to automorphism groups of fundamental groups of graphs of groups in which the edge groups are incomparable up to conjugacy.

ISSN:0092-7872    

DOI:10.1080/00927879908826725

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927879908826726

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

摘要:

The main result in this paper is that the. projective dimension of the nth order universal module of the. coordinate ring of the product of a reduced hypersurface and an affine t-spa.ee is finite. This question appears in [1]. We have seen this by showing that projective dimension of the nth order universal module of the ring corresponding to a reduced hypersurface is finite. At the end we present some examples related to projective dimension of the universal modules of the product of variaties.

ISSN:0092-7872    

DOI:10.1080/00927879908826727

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927879908826728

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor

摘要:

In this paper we continue with the study in any characteristic of equisingularity in codimension 1 started in [G-M]. The whclly general concept of equivalent singularities for plane curves introduced in [G-M] and [G-S], allows us to set out equisingularity in codimenson 1 in the case of positive characteristic, even in the non- equicharac-teristic and non-reduced cases. In this situation, we show the natural algebraic properties of equisingularity in codimension 1: good beharvior by monoidal dilatations, equisingularity of all special sections, characterization of the singular locus, etc. We also prove an equisingularity criterion which coincides with Lemma of [A2].

ISSN:0092-7872    

DOI:10.1080/00927879908826729

出版商:Gordon and Breach Science Publishers Ltd.    

年代:1999

数据来源: Taylor