拟环为拟除环的几个条件

我们定义了左、右不变拟了环和完全亚直既约拟环，给出了拟环为拟除环的几个条件．这些结果可以直接推广到结合环．     

算子的拟仿射变换与拟仿射逆

设H是可分的复Hilbert空间,B(H)是H上全体有界线性算子的代数。以后把B(H)的元简单地叫做算子。对于算子T∈B(H),用R(T)、N(T)、σ(T)及LatT分别表示其值域、零空间、谱及不变子空间的格。算子X∈B(H)叫做拟仿射,如果它满足N(X)=N(X~*)={0}。若T、S、X∈B(H),X是拟仿射,TX=XS,则S叫做T的拟仿射变换。与此类似的一个概念是:若TXS=X,X是拟仿射,则T(S)叫做S(T)的左(右)拟仿射逆([1])。在§1中,找到了有左(右)拟仿射逆的算子是可逆的一些     

拟圆的一个充分必要条件

利用拟双曲度量研究了平面拟共形映照中的拟圆，得到了拟圆的一个充分必要条件。     

拟共不变集和拟圆的特征

证明了ＮＥＤ集在拟共形映照下的像仍是ＮＥＤ集，建立了关于拟圆的一个充分必要条件。     

2×2分块对角算子矩阵拟谱的精细刻画

设A,B为可分Hilbert空间X中的稠定闭线性算子,■表示2×2分块算子矩阵.文中精细刻画算子矩阵M₀在对角扰动情形下的拟点谱、拟剩余谱与拟连续谱,所得结论与点谱、剩余谱和连续谱的结果进行了比较,并用例子进行了辅证.最后,采用空间分解技巧,用主对角元的信息刻画M₀在上三角扰动情形下的拟点谱分布.     

广义拟Newton法及其收敛性定理

1引言设R~n.R_+n.R_+~n分别表示Euclidean空间及R~n的非负和正子空间：符号┃·┃表示向量或矩阵的2-范数，非线性互补问题（NLCP）     

拟酉矩阵与拟Hermite矩阵

利用次Hermite矩阵给出了拟酉矩阵与（反）拟Hermite矩阵的概念,研究了它们的基础本性质及其之间的关系,将各类酉矩阵与Hermite矩阵一了起来。     

量化Domain理论的L-Fuzzy式处理(Ⅱ)L-Fuzzy拟序集的表示

本文是文献的续。对于固定的Frame L，本文证明了每个LF-拟序集可以等价地表示为拟序的层，该结果与L-Fuzzy集的分解和表示定理类似。由这此定理可得出以下结论：一类量化Domain(例如，广义超度量Domain)实际上是将满足一定条件的拟序族进行“粘贴”的结果(按照层论的语言叙述，就是拟序的层)，而通常的拟序则是常值拟序层的特例。     

拟邻域算子集合的基数

本文引出的0、Ⅰ、Ⅱ、Ⅲ型的拟邻域空间是拓扑空间不同程度的弱化与推广,在首先证明Ⅲ—型空间的闭包算子(?)具有性质 ①(?)=(?)(X)=X ②A(?)(A)③A(?)B(?)(A)(?)(B),及其逆命题的基础上给出了以下结果:|K_m(X)|=|D(X)|=|K_Ⅲ(X)/≌|=|D(X)/≌|=(?)。     

内球性质和拟共形映射

研究了一类具有内球性质区域的几何与分析性质,证明了f(∞)=∞的同胚f:-Rn→-Rn是拟共形映射当且仅当f保持区域的内球性质不变,并获得了该类区域若干有趣的几何性质.     

Scalarization of Henig Proper Efficient Points in a Normed Space

In a general normed space equipped with the order induced by a closed convex cone with a base, using a family of continuous monotone Minkowski functionals and a family of continuous norms, we obtain scalar characterizations of Henig proper efficient points of a general set and a bounded set, respectively. Moreover, we give a scalar characterization of a superefficient point of a set in a normed space equipped with the order induced by a closed convex cone with a bounded base.     

Staircase Parameterization in Dynamical Selection

This paper deals with a variant of a dynamical selection scheme introduced by Attouch and Cominetti for ill-posed convex minimization which combines approximation with the steepest descent method by mean of a suitable parameterization of the approximation parameter as a function of the time. This variant applies to a general inclusion with a maximal monotone operator by mean of a staircase parameterization. A discrete analogue is also considered. Applications to selecting a particular zero of a maximal monotone operator or a particular fixed point of a nonexpansive mapping via regularization techniques are presented. Finally, the alternative use of well-posedness by perturbations is discussed.     

On arithmetic Macaulayfication of Noetherian rings

The Rees algebra is the homogeneous coordinate ring of a blowing-up. The present paper gives a necessary and sufficient condition for a Noetherian local ring to have a Cohen-Macaulay Rees algebra: A Noetherian local ring has a Cohen-Macaulay Rees algebra if and only if it is unmixed and all the formal fibers of it are Cohen-Macaulay. As a consequence of it, we characterize a homomorphic image of a Cohen-Macaulay local ring. For non-local rings, this paper gives only a sufficient condition. By using it, however, we obtain the affirmative answer to Sharp's conjecture. That is, a Noetherian ring having a dualizing complex is a homomorphic image of a finite-dimensional Gorenstein ring.

     

An algorithm for constructing star-shaped drawings of plane graphs

A straight-line planar drawing of a plane graph is called a convex drawing if every facial cycle is drawn as a convex polygon. Convex drawings of graphs is a well-established aesthetic in graph drawing, however not all planar graphs admit a convex drawing. Tutte [W.T. Tutte, Convex representations of graphs, Proc. of London Math. Soc. 10 (3) (1960) 304–320] showed that every triconnected plane graph admits a convex drawing for any given boundary drawn as a convex polygon. Thomassen [C. Thomassen, Plane representations of graphs, in: Progress in Graph Theory, Academic Press, 1984, pp. 43–69] gave a necessary and sufficient condition for a biconnected plane graph with a prescribed convex boundary to have a convex drawing.In this paper, we initiate a new notion of star-shaped drawing of a plane graph as a straight-line planar drawing such that each inner facial cycle is drawn as a star-shaped polygon, and the outer facial cycle is drawn as a convex polygon. A star-shaped drawing is a natural extension of a convex drawing, and a new aesthetic criteria for drawing planar graphs in a convex way as much as possible. We give a sufficient condition for a given set A of corners of a plane graph to admit a star-shaped drawing whose concave corners are given by the corners in A, and present a linear time algorithm for constructing such a star-shaped drawing.     

A Barrier Function Method for the Nonconvex Quadratic Programming Problem with Box Constraints

In this paper a barrier function method is proposed for approximating a solution of the nonconvex quadratic programming problem with box constraints. The method attempts to produce a solution of good quality by following a path as the barrier parameter decreases from a sufficiently large positive number. For a given value of the barrier parameter, the method searches for a minimum point of the barrier function in a descent direction, which has a desired property that the box constraints are always satisfied automatically if the step length is a number between zero and one. When all the diagonal entries of the objective function are negative, the method converges to at least a local minimum point of the problem if it yields a local minimum point of the barrier function for a sequence of decreasing values of the barrier parameter with zero limit. Numerical results show that the method always generates a global or near global minimum point as the barrier parameter decreases at a sufficiently slow pace.     

Genus fields of Kummer extensions of rational function fields

In this paper we obtain the genus field of a general Kummer extension of a global rational function field. We study first the case of a general Kummer extension of degree a power of a prime. Then we prove that the genus field of a composite of two abelian extensions of a global rational function field with relatively prime degrees is equal to the composite of their respective genus fields. Our main result, the genus of a general Kummer extension of a global rational function field, is a direct consequence of this fact.     

Box-Rectangular Drawings of Plane Graphs

In this paper we introduce a new drawing style of a plane graph G called a box-rectangular drawing. It is defined to be a drawing of G on an integer grid such that every vertex is drawn as a rectangle, called a box, each edge is drawn as either a horizontal line segment or a vertical line segment, and the contour of each face is drawn as a rectangle. We establish a necessary and sufficient condition for the existence of a box-rectangular drawing of G. We also give a linear-time algorithm to find a box-rectangular drawing of G if it exists.     

On farthest points of sets

For a convex closed bounded set in a Banach space, we study the existence and uniqueness problem for a point of this set that is the farthest point from a given point in space. In terms of the existence and uniqueness of the farthest point, as well as the Lipschitzian dependence of this point on a point in space, we obtain necessary and su.cient conditions for the strong convexity of a set in several infinite-dimensional spaces, in particular, in a Hilbert space. A set representable as the intersection of closed balls of a fixed radius is called a strongly convex set. We show that the condition “for each point in space that is sufficiently far from a set, there exists a unique farthest point of the set” is a criterion for the strong convexity of a set in a finite-dimensional normed space, where the norm ball is a strongly convex set and a generating set.     

On a Mathematical Comparison between Hierarchy and Network with a Classification of Coordination Structures

This paper proposes a mathematical model to compare a network organization with a hierarchical organization. In order to formulate the model, we define a three-dimensional framework of the coordination structure of a network and of other typical coordination structures. In the framework, we can define a network structure by contrasting it with a hierarchy, in terms of the distribution of decision making, which is one of the main features of information processing. Based on this definition, we have developed a mathematical model for evaluating coordination structures. Using this model, we can derive two boundary conditions among the coordination structures with respect to the optimal coordination structure. The boundary conditions help us to understand why an organization changes its coordination structure from a hierarchy to a network and what factors cause this change. They enable us, for example, to find points of structural change where the optimal coordination structure shifts from a hierarchy to a hierarchy with delegation or from a hierarchy with delegation to a network, when the nature of the task changes from routine to non-routine. In conclusion, our framework and model may provide a basis for discussing the processes that occur when coordination structures change between a hierarchy and a network.