Some New Combinatorial Conditions on the Singular Fibre of a Fibration

Ｓｏｍｅ　Ｎｅｗ　Ｃｏｍｂｉｎａｔｏｒｉａｌ　Ｃｏｎｄｉｔｉｏｎｓ　ｏｎ　ｔｈｅ　Ｓｉｎｇｕｌａｒ　Ｆｉｂｒｅ　ｏｆ　ａ　ＦｉｂｒａｔｉｏｎＴａｎｇＭｉｎｇｙｙｕａｎ（唐明元）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＳｈａｎｇｈａｉＮｏｒｍ...     

Invex Functions and Generalized Convexity in Multiobjective Programming

Martin (Ref. 1) studied the optimality conditions of invex functions for scalar programming problems. In this work, we generalize his results making them applicable to vectorial optimization problems. We prove that the equivalence between minima and stationary points or Kuhn–Tucker points (depending on the case) remains true if we optimize several objective functions instead of one objective function. To this end, we define accurately stationary points and Kuhn–Tucker optimality conditions for multiobjective programming problems. We see that the Martin results cannot be improved in mathematical programming, because the new types of generalized convexity that have appeared over the last few years do not yield any new optimality conditions for mathematical programming problems.     

我国各地农民家庭消费结构分析

本文运用聚类分析和主成分分析等统计方法，对我国３０个省、自治区、直辖市的农民家庭的消费结构进行聚类和分析，找出影响我国农民家庭消费结构的因素，为经济研究提供科学依据．     

Banach空间中渐近拟非扩展型映象不动点的迭代逼近

本文研究了一致凸Banach空间中渐近拟非扩展型映象和渐近非扩展型映象T的不动点的迭代逼近问题.利用范数不等式，在去掉[3]中一个较强条件的情况下，证明了T的具误差的Ishikawa迭代序列中收敛于T的某个不动点.所得定理推广和改进了已有的部分结果。     

Resolutions of ideals of any six fat points in

The graded Betti numbers of the minimal free resolution (and also therefore the Hilbert function) of the ideal of a fat point subscheme Z of P² are determined whenever Z is supported at any 6 or fewer distinct points. All results hold over an algebraically closed field k of arbitrary characteristic.     

L─fts中的导集和导算子

本文首先讨论了Ｌ─ｆｔｓ中ＬＦ集的聚点的分布；其次讨论了ＬＦ集的导集的一些性质，并给出了一般的Ｌ─ｆｔｓ中类似于杨忠道定理的结果；本文最后引进了导算子的概念，并用其刻划一般的Ｌ─ｆｔｓ．     

拟常曲率流形中全脐点子流形的拼嵌定理

We study the global umbilic submanifolds with parallel mean curvature vector fields in a Riemannian manifold with quasi constant curvature and get a local pinching theorem about the length of the second fundamental form.     

Banach空间中非Lipschitz的渐近伪压缩映象不动点的迭代逼近问题

本文在去掉条件“‖Tnxn-xn‖→0(n→∞)”的情况下,在任意实的Banach空间中研究了用具误差的修正的Ishikawa与Mann迭代程序来逼近非Lipschitz的渐近伪压缩映象不动点的强收敛性问题;所得结果不但改进和推广了张石生教授与曾六川教授的结果,而且也从根本上改进了定理的证明方法．     

The expected number of extreme points of a random linear program

There has been increasing attention recently on average case algorithmic performance measures since worst case measures can be qualitatively quite different. An important characteristic of a linear program, relating to Simplex Method performance, is the number of vertices of the feasible region. We show 2 ⁿ to be an upper bound on the mean number of extreme points of a randomly generated feasible region with arbitrary probability distributions on the constraint matrix and right hand side vector. The only assumption made is that inequality directions are chosen independently in accordance with a series of independent fair coin tosses.We would like to thank the Institute of Pure and Applied Mathematics in Rio de Janeiro for supporting the authors' collaboration that led to this paper.