Hamiltonian circle actions on symplectic manifolds and the signature

Let M be a symplectic manifold with a Hamiltonian circle action with isolated fixed points. We prove that σ (M) = b₀(M) − b₂(M) + b₄(M) − b₆(M) + … where σ (M) is the signature of M and b_i(M) is the ith Betti number of M.     

Orbifold fibrations of Eschenburg spaces

Most of the few known examples of compact Riemannian manifolds with positive sectional curvature are the total space of a Riemannian submersion. In this article we show that this is true for all known examples, if we enlarge the category to orbifold fibrations. For this purpose we study all almost free isometric circle actions on positively curved Eschenburg spaces, which give rise to principle orbifold bundle structures, and we examine in detail their geometric properties. In particular, we obtain a new family of 6-dimensional orbifolds with positive sectional curvature whose singular locus consists of just two points.      

Graphs with Special Arcs and Cryptography

A combinatorial method of encryption with a similarity to the classical scheme of linear coding has been suggested by the author. The general idea is to treat vertices of a graph as messages and arcs of a certain length as encryption tools. We will study the quality of such an encryption in the case of graphs of high girth by comparing the probability to guess the message, (vertex) at random with the probability of breaking the key, i.e. guessing the encoding arc. In fact, the quality is good for graphs which are close to the Erdös bound, defined by the Even Cycle Theorem.In the case of parallelotopic graphs, there is a uniform way to match arcs with strings in a certain alphabet. Among parallelotopic graphs we distinguish linguistic graphs of affine type whose vertices (messages) and arcs (encoding tools) both could be naturally identified with vectors over the GF(q), and neighbors of the vertex defined by a system of linear equations. We will discuss families of linguistic and parallelotopic graphs of increasing girth as the source for assymmetric cryptographic functions and related open key algorithms.Several constructions of families of linguistic graphs of high girth with good quality, complexity and expansion coefficients will be considered. Some of those constructions have been obtained via group-theoretical and geometrical techniques.     

我国检察民事公诉:问题与前瞻

检察民事公诉是指针对部分涉及国家利益和社会公共利益等方面的民事案件而由检察机关代表国家提起的诉讼。该制度已被世界许多国家民事诉讼制度所吸纳。在我国，由于危害公共利益的社会公害层出不穷，同时亦基于检察机关自身的性质，建立检察机关民事公诉制度已势在必行。我国现行立法在检察民事公诉方面存在严重局限，因此，探讨检察机关在民事公诉中的法律地位及其参与民事公诉的方式和范围将有着重大的现实意义。     

Spectrum of positive entropy multidimensional dynamical systems with a mixed time

It is shown that if an abelian countable group is such that is a finite group and every aperiodic positive entropy action of on a Lebesgue probability space has a countable Haar spectrum in the subspace , where denotes the Pinsker -
algebra of , then every aperiodic positive entropy action of on has the same property. A positive answer to the question of J.P. Thouvenot is obtained as a corollary.

     

加强政府投资项目合同管理防止集体腐败行为的发生

政府投资项目的多层级代理容易诱发集体腐败行为，表现在合同管理中就是业主、承包商与监理单位及监理工程师彼此串通，通过虚增工程量等手段来多领工程款，这些行为严重影响了我国政府投资项目的效益。对发达国家通过加强政府投资项目合同的政府管理来防止集体腐败的做法进行了分析，对其值得借鉴之处进行了总结，并针对我国的具体情况，提出了加强政府投资项目合同管理的若干合理化建议。     

非强制性行政行为的法律思考

随着我国经济的发展和社会的进步,依法治国方略正得到一步步的贯彻落实,和谐社会的理念也正在深入人心,行政行为的多样化作为未来行政行为的发展方向,必然对我国的行政管理产生重大的影响,行政行为的多样化是实现行政管理领域和谐的关键。     

学生技术动作学习中纠错方法的心理学原理

在技术动作教学过程中，教师纠正学生练习中的动作错误，必须按照学生运动技能形成的规律，合理地选择使用纠错的方法，才能收到良好的纠错效果。主要从学生运动技能学习形成的规律出发，阐述了在学生运动技能学习的不同阶段，教师使用运动感知、运动表象、运动概念和语言等纠错方法的心理学依据，对一些常用纠错方法做了心理学解释。     

智能规划中互斥动作延迟算法

为解决扩张规划图时某一时间步出现的互斥动作的延迟问题，引进了无序要求互斥动作和有序要求互斥动作的概念，并且在此基础上，给出互斥动作延迟算法．利用这一算法生成的规划图，在进行有效规划的搜索时是非常方便的．     

激光与光学薄膜的相互作用机制

应用激光与光学薄膜作用产生的等离子体形貌,研究了该作用过程和机理,实验结果与之吻合。