关于W．Y．Velez猜想

设F为域,ψ为F的秩为1的非平凡,非阿基米德赋值,r为与其相对应的赋值环,p为r的极大理想,本文讨论了F的m次根扩张中的素理想分解问题,当基域中含有m次本原单位根时,完全解了W．Y．Velez问题。     

W．J．LeVeque的一个定理的注记

本文证明了：对固定的正整数α，β．ｍ，其中ｍ≥２，若方程　有无穷多个正整数解ｎ，则ｍ＝２，α＝３及β＝１．这推广了ＬｅＶｅｑｕｅ的一个结果。     

I．J．Matrix定理的再推广

名一+.、、、.产了 文〔l」用初等方法证明:设二.,九,…,:。是。个不为零的且互不相同的数,则兰军里「TT,JLII名一+(生+生+交_‘一星)卜‘高11(‘,一‘。)11‘,(r=一1).皿‘奋‘月 告产矛+(‘工丫+生生十…、:一2十… \\劣一/劣一劣2/但对,<一I时未作讨论.为此,本文将给出,《一l的一般结论.其次,我们还将从另一方面推广文[1]的结果,并给出部分结果的一个较为实用的证法. 定理相同的教,l设::,…,:.是旅个不为零且互不则对任意自然数。,有 二万.逐项积分,由于告f少一1(因方向是一’一’~’一2石场.“一、一,二’’J_负的).故除z一’的系数…     

次Jacobi．Gauss—Seidel．Sor迭代法

次Ｊａｃｏｂｉ．Ｇａｕｓｓ—Ｓｅｉｄｅｌ．Ｓｏｒ迭代法刘玉波（天津大学冶金分校）在计算线性方程组时，我们有时会遇到其系数矩阵Ａ是严格次对角占优①及次正定的次对称的情形。对于这样的方程组，我们不能直接应用Ｊａｃｏｂｉ，Ｇａｕｓｓ—Ｓｅｉｄｅｌ及超松驰迭...     

i．i．d随机变量随机和的数字特征

讨论了i．i．d的随机变量随机和的数学期望和方差、特征函数以及矩母函数的计算公式。并对求和个数服从几何分布和Possion分布，随机变量服从指数分布时给出了直接结果．     

A Simple Method for Computing the Homeomorphism Class of G． M．  and G． M． 

Ａ　Ｓｉｍｐｌｅ　Ｍｅｔｈｏｄ　ｆｏｒ　Ｃｏｍｐｕｔｉｎｇ　ｔｈｅ　Ｈｏｍｅｏｍｏｒｐｈｉｓｍ　Ｃｌａｓｓ　ｏｆ　Ｇ．　Ｍ．　　ａｎｄ　Ｇ．　Ｍ．　ＡＳｉｍｐｌｅＭｅｔｈｏｄｆｏｒＣｏｍｐｕｔｉｎｇｔｈｅＨｏｍｅｏｍｏｒｐｈｉｓｍＣｌａｓｓｏｆＧ...     

对格上Erceg式p．q．（p．）度量的注记

本文的主要结果是大幅度地简化了Ｅｒｃｅｇ引入的不分明度量的无点化定义，建立了相应的点式刻画．     

不可微D．C．规划的最优性条件

不可微Ｄ．Ｃ．规划的最优性条件李忠民，边欣（天津大学）（天津教育学院）在非凸不可微规划中，有两种重要类型：ｓｕｐ｛ｇ（ｘ）：。６Ｃ｝，：Ｔ。ｉｎｆ｛ｇ（ｘ）一ｈ（ｘ）：。ｅＣ｝，》其中ｑ、ｈ：Ｒ，＋Ｒ是不可微的凸函数，Ｃ是Ｒ·上的ＩＷ凸集。文【１］在...     

C．R．Rao不等式的简单证明

引进多边矩阵理论中的分解算子,对单位阵进行正交投影分解,再利用投影矩阵秩等于迹及矩阵秩≥0的性质,给出了C.R.Rao不等式的一个简单证明.     

ESTIMATION OF SCATTER MATRIX BASED ON i．i．d． SAMPLE FROM ELLIPTICAL DISTRIBUTIONS

ＥＥＳＴＩＭＡＴＩＯＮＯＦＳＣＡＴＴＥＲＭＡＴＲＩＸＢＡＳＥＤＯＮｉ．ｉ．ｄ．ＳＡＭＰＬＥＦＲＯＭＥＬＬＩＰＴＩＣＡＬＤＩＳＴＲＩＢＵＴＩＯＮＳ￥ＦＡＮＧＫＡＩＴＡＩ（方开泰）（ＩｎｓｔｉｔｕｔｅｏｆＡＰＰｌｉｅｄＭａｔｈｅｍａｔｉｃｓ,ｔｈｅＣｈｉ...     

Two-point b.v.p. for multivalued equations with weakly regular r.h.s.

A two-point boundary value problem associated to a semilinear multivalued evolution equation is investigated, in reflexive and separable Banach spaces. To this aim, an original method is proposed based on the use of weak topologies and on a suitable continuation principle in Fréchet spaces. Lyapunov-like functions are introduced, for proving the required transversality condition. The linear part can also depend on the state variable x and the discussion comprises the cases of a nonlinearity with sublinear growth in x or of a noncompact valued one. Some applications are given, to the study of periodic and Floquet boundary value problems of partial integro-differential equations and inclusions appearing in dispersal population models. Comparisons are included, with recent related achievements.     

The E.E.C. and the development of O.R.

The growth of the E.E.C. has brought about a change in the scale of many organizational problems and a change in the ways that they can be tackled. Accordingly it is plausible that the techniques of O.R. should develop in response to these changes. This paper examines some desirable developments and suggests ways in which they might be achieved by adapting methods devised in other fields for similar problems.     

D.c. sets,d.c. functions and nonlinear equations

Ad.c. set is a set which is the difference of two convex sets. We show that any set can be viewed as the image of a d.c. set under an appropriate linear mapping. Using this universality we can convert any problem of finding an element of a given compact set in ⁿ into one of finding an element of a d.c. set. On the basis of this approach a method is developed for solving a system of nonlinear equations—inequations. Unlike Newton-type methods, our method does not require either convexity, differentiability assumptions or an initial approximate solution.The revision of this paper was produced during the author's stay supported by a Sophia lecturing-research grant at Sophia University (Tokyo, Japan).     

Selectively c.c.c. spaces

We present a study about a natural way of defining a selective version of the c.c.c. property. This definition and some related properties were already considered under different names in other works, such as Daniels et al. (1994) [9], Scheepers (2000) [12]. Here we will present some of its relations with other selective properties and we present some examples that show the differences among the properties considered. We also study the behavior of these properties when the products are considered.     

A Quasi Fixed-Point Theorem for a Product of u.s.c. or o.l.s. Correspondences with an Economic Application

In the first place, we present a quasi fixed-point theorem for a correspondence defined on some infinite-dimensional locally convex topological vector space such that some variables have open lower sections and the other ones are upper semicontinuous.In the second place, we propose a direct application of the quasi fixed-point result in an economic model. More precisely, we prove a nonemptiness result of the core of an exchange economy with asymmetric information, a continuum of states and a finite number of commodities.     

Optimization of the Relaxation Parameter for S.S.O.R. and A.D.I. Preconditioning

We present and compare several approaches for the optimization of the relaxation parameter both for A.D.I. and S.S.O.R. basic iteration and preconditioning conjugate gradient method. For each kind of preconditioning a detailed link between estimates of the spectral radius of the iteration matrix and of the condition number resulting from preconditioning is proposed. It allows to choose the best approach in order to obtain the optimal relaxation parameter and the corresponding optimal estimates either of the spectral radius of the iteration matrix and of the resulting condition mumber of the S.S.O.R. and A.D.I. preconditioning.     

On the r.e. predecessors of d.r.e. degrees

Let d be a Turing degree containing differences of recursively enumerable sets (d.r.e.sets) and R[d] be the class of less than d r.e. degrees in whichd is relatively enumerable (r.e.). A.H.Lachlan proved that for any non-recursive d.r.e. d R[d] is not empty. We show that the r.e. degree defined by Lachlan for a d.r.e.set d is just the minimum degree in which D is r.e. Then we study for a given d.r.e. degree d class R[d] and show that there exists a d.r.e.d such that R d] has a minimum element 0. The most striking result of the paper is the existence of d.r.e. degrees for which R[d] consists of one element. Finally we prove that for some d.r.e. d R[d] can be the interval [a,b] for some r.e. degrees a,b, a b d. Received: 17 January 1996     

Pioneering O.R.

This paper describes the critical start-up period of a new Operational Research unit in industry. Four principles for success evolved and are discussed against a background of practical work.     

S.A.G.B.I. bases for rings of formal modular seminvariants

We use the theory of S.A.G.B.I. bases to construct a generating set for the ring of invariants for the four and five dimensional indecomposable modular representations of a cyclic group of prime order. We observe that for the four dimensional representation the ring of invariants is generated in degrees less than or equal to 2p–3, and for the five dimensional representation the ring of invariants is generated in degrees less than or equal to 2p–2. Received: January 22, 1997     

Choosing the Operational Research Programme for B.I.S.R.A

This paper examines some important problems in the evaluation and selection of research projects, with particular reference to operational research projects in a central industry research organization. A method for project evaluation is suggested which provides data suitable for use in a powerful and flexible formal procedure for project selection. In evaluating a project, the assessment of resource requirements is based on a probabilistic network plan of the project, and the estimates of benefits are derived from the marginal effects on the industry of performing or not performing the project, using discounted cash flow techniques. The procedure for project selection chooses not only the projects to be undertaken, but also the team sizes that should be used. A wide variety of constraints can be imposed on the system to reflect different aspects of management policy or other special factors. The procedures described have been implemented, and have proved well worth while.