二维晶格上Kadanoff分块及重整化群方法

对二维晶格上的Kadanoff分块进行了全面分析，给出了划分的一般规律，得出元块选择的非任意性和含相同元块选择不惟一等结论，并给出正三角形格子和正方形格子元块中格点数目的允许值。同时，利用重整化群方法对9点，13点元块进行了计算，得到了相应的不动点和各种临界指数，并与其它计算结果进行了比较，结果表明，计算精度有随元块中所含格点数的增加而增加的趋势。     

Isometric Actions of Heisenberg Groups on Compact Lorentz Manifolds

We prove results toward classifying compact Lorentz manifolds on which Heisenberg groups act isometrically. We give a general construction, leading to a new example, of codimension-one actions – those for which the dimension of the Heisenberg group is one less than the dimension of the manifold. The main result is a classification of codimension-one actions, under the assumption they are real-analytic.     

Deterministic chaos in one-dimensional maps—the period doubling and intermittency routes

This paper is a review of the present status of studies relating to occurrence of deterministic chaos and its characterization in one-dimensional maps. As our primary aim is to introduce the nonspecialists into this fascinating world of chaos we start from very elementary concepts and give sufficient arguments for clarity of ideas. The two main scenarios during onset of chaos viz. the period doubling and intermittency are dealt with in detail. Although the logistic map is often discussed by way of illustration, a few more interesting maps are mentioned towards the end.     

Large 2-transitive arcs

The projective planes of order n with a collineation group acting 2-transitively on an arc of length v, with n>v?n/2, are investigated and several new examples are provided.     

Dirac cohomology of unitary representations of equal rank exceptional groups

In this paper, we consider the unitary representations of equal rank exceptional groups of type E with a regular lambda-lowest K-type and classify those unitary representations with the nonzero Dirac cohomology.     

Dominions in varieties generated by simple groups

We determine the dominion (in the sense of Isbell) of a subgroup H of a finite nonabelian simple group S in Var(S). We also obtain necessary and suficient conditions for H to be epimorphically embedded in S, and derive several examples, which generalize an example of B. H. Neumann. Finally, we extend the results to a variety generated by a family of finite nonabelian simple groups. Received May 12, 1999; accepted in final form April 9, 2002.     

非可换的奇异l-群

通过建立奇异元以及奇异l-群的刻划，研究了一般非可换的奇异l-群的性质及相关的结构．     

Crystallized structure for level 0 part of modified quantum affine algebra Uq (sl2)

Crystal base of the level 0 part of the modified quantum affine algebra Uq(sl2)_0 is given by path. Weyl group actions, extremal vectors and crystal structure of all irreducible components are described explicitly.     

微分流形上的变换群

本文主要讨论如何把仿射Ｋｉｌｌｉｎｇ向量场、共形Ｋｉｌｌｉｎｇ向量场和射影Ｋｉｌｌｉｎｇ向量场推广成为四种张量场．我们得到了仿射Ｋｉｌｌｉｎｇｐ（≥１）形式和射影Ｋｉｌｌｉｎｇｐ（≥１）形式的多种定义，文献［１］中的定义仅是其中之一．     

最小二乘—红外光谱法定量测定羟基化合物

根据羟基伸缩振动吸收带的特性，用最小二乘法有效消除了溶液中羟基间的缔合作用对测定结果的影响。此方法已用于聚合物中羟基含量的测定。