正则FI代数的若干性质

讨论正则FI代数的若干性质。在研究FI代数与Boole代数间关系的同时,给出正则FI代数与BCK代数的另一种联系方式。     

AS-Gorenstein代数的Yoneda代数

令A为诺特基本k-代数,设J为其Jacobson根且半单代数A/J同构于有限个k的直积.证明了如果A是AS-Gorenstein代数,则其Yoneda代数Ext*A(A/J,A/J)是Frobenius代数;如果A的内射维数injdimAA=d,则函子ExtdA(-,A)是可表示的.     

关联BCI—代数

一个BCK-代数叫做关联的,如果它满足 (1).x*(y*x)=x K.Is’eki[2]证明了满足(1)的BCI-代数是一个BCK-代数。于是为了引入关联BCI-代数概念,先给出关联BCK-代数的等价条件。本文将不加说明地引用[1]中的记号和结论。     

算子代数的斜积

引入了算子代数的一种新运算"斜积",证明了在这个新定义的斜积运算下算子代数的自反性保持不变.研究发现,斜积运算对应的子空间格是拓扑意义下的格的直积关系.这个新发现的重要意义在于由此可从已知的自反子空间格生成更多更复杂的新自反格,从而得到新的自反代数.在此基础上,本文对KS-代数保持性等其他非自伴代数类的性质也作了相应研究.     

一些无限维完备李代数

本文讨论了无限维完备李代数的一些性质,由Virasoro代数,Kac-Moody代数构造了几类无限维完备李代数.同时给出了Kac-Moody代数及其广义抛物子代数的导子代数的刻划.证明了完备李代数的Loop扩张仍为完备李代数.     

伪补对称扩张Ockham代数

研究peO代数类中的子类pe_(2,0)K_(1,1),即满足恒等式f~3=f和k~2=id_L的peO-代数.利用同余和代数的次直不可约,有如下的主要结果:如果L∈pe_(2,0)K_(1,1),则L是真次直不可约当且仅当Con L■{ω}[G,Φ]{ι}.这里ω和l分别表示相等关系和泛关系,Φ表示由f(x)=f(y)确定的一个同余,G表示Glivenko同余.     

量子包络代数借助Hopf代数的扩张

设H是Hopf代数,g是由Cartan矩阵A=(a_(ij))_(I×I)决定的广义Kac-Moody代数,这里的I是指标集,它或者是有限个整数{1,2,…,n},或者是整个自然数集N,用f,g表示从I到Hopf代数H的群象元素集G(H)两个映射,假如集合{f(i),g(i)|i∈I}中任何两个元素乘法可以交换,则可以在H(?)_g~f U_q(g)上定义一种Hopf结构,这里的U_q(g)是g量子包络代数.     

分配的Fuzzy蕴涵代数

给出了分配的Fuzzy蕴涵代数的定义并探讨了其有关性质，接着本文证明了分配的Fuzzy蕴涵代数与Boole代数、正则的HFI代数是相互等价的，从而得到Boole代数的两个等价形式，并且证明了分配的Fuzzy蕴涵代数是BL代数，最后得到了FI代数成为Boole代数的几个充要条件。     

QF代数的Hopf代数作用

Ｈ是 Ｈｏｐｆ代数，Ａ是左 Ｈ－模代数，本文给出了当 Ａ是 ＱＦ代数时，ＡＨ也是 ＱＦ代数的一个条件．     

有限关联BCK—代数

本文主要讨论有限关联BCK-代数的存在性结构和个数问题。命题1 设N’是全体正无平方因子数的集合。若在N’上定义二元运算     

Certain Diophantine Properties of the Mahler Measure

It is proved that a polynomial in several Mahler measures with positive rational coefficients is equal to an integer if and only if all these Mahler measures are integers. An estimate for the distance between a metric Mahler measure and an integer is obtained. Finally, it is proved that the ratio of two distinct Mahler measures of algebraic units is irrational.     

Algebraic cocycles on normal, quasi-projective varieties

This paper extends to quasi-projective varieties earlier work by the author and H. Blaine Lawson concerning spaces of algebraic cocycles on projective varieties. The topological monoid C_r(Y) (U) of effective cocycles on a normal, quasi-projective variety U with values in a projective variety Y consists of algebraic cycles on U×Y equi-dimensional of relative dimension r over U. A careful choice of topology enables the establishment of various good properties: the definition is essentially algebraic, the group completion Z_r (Y) (U) has 'sensible' homotopy groups, the construction is contravariant with respect to U, convariant with respect to Y, and there is a natural 'quality map" to the topological group of cycles on U×Y. The fundamental theorem presented here is the extension of Friedlander-Lawson duality to this context: the duality map Z_r (Y) (U) to Z_{_r+m} (U × Y) is a homotopy equivalence provided that both U and Y are smooth (where m=dim U). Various application are given, especially the determination of the homotopy types of certain topological groups of algeb raic morphisms.     

线性空间上凸函数的可微性与次可微性

讨论了定义在线性空间上的广义实值凸函数的可做性和次可微性．     

代数系数幂级数在超越数上值的代数无关性

本文证明了一类具有代数系数的幂级数在超越数上值约代数无关性．     

Minimal invariant varieties and first integrals for algebraic foliations

Let X be an irreducible algebraic variety over ℂ, endowed with an algebraic foliation . In this paper, we introduce the notion of minimal invariant variety V( , Y) with respect to ( , Y), where Y is a subvariety of X. If Y = {x} is a smooth point where the foliation is regular, its minimal invariant variety is simply the Zariski closure of the leaf passing through x. First we prove that for very generic x, the varieties V( , x) have the same dimension p. Second we generalize a result due to X. Gomez- Mont (see [G-M]). More precisely, we prove the existence of a dominant rational map F : X → Z, where Z has dimension (n − p), such that for very generic x, the Zariski closure of F⁻¹(F(x)) is one and only one minimal invariant variety of a point. We end up with an example illustrating both results.     

对话李克正教授：为什么学习代数几何

以与首都师范大学的李克正教授对话的方式,通过其口简要介绍代数几何这门重要学科在我国的早期发展情况,详细回忆李克正教授在国外学习代数几何的过程,以及他回国后的教学与研究成果,并通俗地阐述代数几何方法对于解决重大数论问题所起的关键作用．     

实分片代数曲线的某些研究

分片代数曲线作为二元样条函数的零点集合是经典代数曲线的推广. 利用代数的基本知识, 本文对实分片代数曲线的基本性质进行了初步讨论, 并且将实分片代数曲线与相应的二元样条分类进行讨论. 最后, 对实分片代数曲线上的孤立点进行了研究.     

弱代数性自反与强代数性自反

Algebraic reflexivity introduced by Hadwin is related to linear interpolation. In this paper, the concepts of weakly algebraic reflexivity and strongly algebraic reflexivity which are also related to linear interpolation are introduced. Some properties of them are obtained and some relations between them revealed.     

Terminal 3-fold Divisorial Contractions of a Surface to a Curve I

Let X be a smooth curve on a 3-fold which has only index 1 terminal singularities along . In this paper we investigate the existence of extremal terminal divisorial contractions E Y X, contracting an irreducible surface E to . We consider cases with respect to the singularities of the general hypersurface section S of X through . We completely classify the cases when S is A _i , i 3, and D _2n for any n.     

关于一类函数的代数逼近度的注记

设A（z)是函数列{fn(z)}的极限函数，已知^[4],当|fn(z)-A(z)|在z=0的阶满足一定的条件时，A（z)是超越函数。本文给出了极限函数的代数逼近度函数。