群众决策的ακ-较多规则

对于群体决策问题,本文给出一个新的带参数的ακ-较多规则,并且讨论了在此规则下个体选优解和群体选优解的关系。此外,还论证了相应的ακ-较多规则满足Arrow公理的情况。     

ON THE SHEAF OF GENERALIZED FUNDAMENTAL GROUP AND COVERING SPACE

ＯＮ ＴＨＥ ＳＨＥＡＦ ＯＦ ＧＥＮＥＲＡＬＩＺＥＤ ＦＵＮＤＡＭＥＮＴＡＬ ＧＲＯＵＰ ＡＮＤ ＣＯＶＥＲＩＮＧ ＳＰＡＣＥ￥ＧＡＮＤＡＮＹＡＮＡｂｓｔｒａｃｔ：Ｔｈｅａｕｔｈｏｒｃｏｎｓｔｒｕｃｔｓｔｈｅｓｈｅａｆｏｆｇｅｎｅｒａｌｉｚｅｄｆｕ...     

EXTENDED OBLIQUE PROJECTION METHOD FOR GENERALIZED LEAST SQUARES PROBLEM

We extend the oblique projection method given by Y.Saad to solve the generalized least squares problem. The corresponding oblique projection operator is presented and the convergence theorems are proved. Some necessary and sufficient conditions for computing the solution or the minimum N-norm solution of the min || A x- b ||M2 have been proposed as well.     

Finite groups in which elements of the same order outside the center are conjugate

We prove that if G is a finite group in which the elements of the same order outside the center are conjugate,then either G is abelian or G(?)S_3.     

Invariant sets and solutions to the generalized thin film equation

The invariant sets and the solutions of the 1 2-dimensional generalized thin film equation are discussed. It is shown that there exists a class of solutions to the equations, which are invariant with respect to the set E0 = {u : ux = vxF(u), uy = vyF(u)}, where v is a smooth function of variables x, y and F is a smooth function of u. This extends the results of Galaktionov (2001) and for the l l-dimensional nonlinear evolution equations.     

o-Formylation of electron-rich phenols with dichloromethyl methyl ether and TiCl4

o-Formylation of electron-rich phenols is accomplished with dichloromethyl methyl ether and TiCl₄. The reaction gives excellent yields, good regioselectivity, and does not leading to diformylation.     

C_(60)衍生物分子的拉曼光谱研究

本文通过对C6 0 衍生物拉曼光谱的研究发现 ,由于有机官能团的出现使得C6 0 分子的结构发生了变化 ,从而导致C6 0 衍生物的拉曼光谱有了明显不同。本文对此现象进行了分析与解释。     

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.