关于一类扰动系统的极限环上界问题

本文讨论了一类扰动系统在其一阶Ｍｅｌｎｉｋｏｖ函数恒为零,而二阶Ｍｅｌｎｉｋｏｖ函数不恒为零时的Ｐｏｉｎｃａｒｅ分支及Ｈｏｐｆ分支的有关问题,得到了该系统的极限环个数的上界估计,本文推广并深化了文「４」的结论,也弥补了该文的某些不足。     

关于M—矩阵等价表征的注记

「２」指出了「１」的某些错误,并给出了修正的结果。本继续「２」的讨论,给出了Ｍ－矩阵等价表征的进一步结果。     

模糊值函数与模糊数积分区间[A,B]上的N—L公式

文「１」给出模糊值函数在普通区间「ａ,ｂ」上的Ｎ－Ｌ公式。本文在文「１」的基础上进一步给出模糊值函数区间「Ａ,Ｂ」上的积分。这个积分是Ⅱ型糊集。文「３」已经指出（Ｆ２「１,１」,∪,∩,ｃ）不是软代数,但这个积分是一个特殊Ⅱ型模糊集具有许多良好的代数性质,并存在着Ｎ－Ｌ公式。     

Banach空间中—u‘’∈F（t,u（t）,u（t））的解

本文给出了弱序列完备Ｂａｎａｃｈ空间中二阶微分包含的解的存在性定理，推广了「１」中的结果到集值情形，同时由于利用已有的定理「２」，简化了类似「１」宫的证明。     

两类求解y“=f（x,y）具有极小相位延迟的显式方法

本文提出了两类数值积分二阶周期性初值问题ｙ〃＝ｆ（ｘ，ｙ），ｙ（ｘ０）＝ｙ０，ｙ（ｘ０）＝ｙ０具有检小相位延迟的显式两步法。这些方法推广和改进了文献「１」１－「７」中的某些方法。数值试验表明本文中的某些方法优于「１」－「７」中的某些方法。     

Menger概率n-度量空间中的不动点定理

引进了概率ｎ－度量空间,并将文「１」、「２」的某些主要结果拓广至Ｍｅｎｇｅｒ概率ｎ－度量空间。     

复数域上有限群代数的中心在整数环上的整闭包

本文运用Ｆｏｕｒｉｅｒ反演公式刻划了复数域Ｃ上的一个有限群Ｇ的群代数Ｃ「Ｇ」的中心Ｚ（Ｃ「Ｇ」）中整数环Ｘ的整闭包,给出了群代数Ｃ「Ｇ」的中心元在整数环Ｚ上为整元的充要条件。     

关于一类变分不等式的迭代算法

本文通过对「１」中相应结构的讨论与改进,利用变分不等式求解技巧,讨论了Ｈｉｌｂｅｒｔ空间中一类广义变分不等式的解的迭代算法及其收敛性,指出了文「１」中主要结果的证明的一些不足之处,本文所得结果推广并改进了「１」的相应结论。     

正定型超曲面上的闭曲线与非线性振荡的周期

本文在Ｒ＾ｎ＋１中定义了一类超曲面并讨论了其上闭测地线上度的下界以及Ｈａｍｉｌｔｏｎ系统的周期解的最小周期，这类超曲面比星形超曲面广泛，因而本文结论包括了文献「１」、「２」、「３」中的相应结论。     

关于迭代序列的子列极限点

本文讨论了度量空间上一个连续自映射在一点处的迭代序列的子列极限点集的结构，所得的结果统一和推广了Ｄｉａｚ和Ｍｅｔｃａｌｆ「１」，Ｍａｉｔｉ和Ｂａｂｕ「２，４」和Ｐａｒｋ「３」的若干结果。     

Inequality for the Moment of a Function of a Random Variable

ＩｎｅｑｕａｌｉｔｙｆｏｒｔｈｅＭｏｍｅｎｔｏｆａＦｕｎｃｔｉｏｎｏｆａＲａｎｄｏｍＶａｒｉａｂｌｅ￥ＬｉＢａｉｎｉａｎＨｕＳｈｕｈｅ（李柏年，胡舒合）（ＡｎｈｕｉＩｎｓｔｉｔｕｔｅｏｆＦｉｎａｎｃｅａｎｄＴｒａｄｅ）（ＡｎｈｕｉＵｎｉｖｅｒｓｉｔｙ...     

动态环境约束下企业的资本积累

本文讨论动态环境约束下企业的动态投资行为,拓广了文献[4]的结果.为了使讨论的问题更符合实际情况,本文假设政府设定的污染排放上限是与企业的规模大小有关,即假设污染排放上限是生产资本的函数,讨论动态环境约束下企业的最佳动态投资行为,并为政府制定污染排放政策提供依据.     

Upper bound and stability of scaled pseudoinverses

Summary. For given matrices and where is positive definite diagonal, a weighed pseudoinverse of is defined by and an oblique projection of is defined by . When is of full column rank, Stewart [3] and O'Leary [2] found sharp upper bound of oblique projections which is independent of , and an upper bound of weighed pseudoinverse by using the bound of . In this paper we discuss the sharp upper bound of over a set of positive diagonal matrices which does not depend on the upper bound of , and the stability of over . Received September 29, 1993 / Revised version received October 31, 1994     

On Approximation by Neural Networks with Optimized Activation Functions and Fixed Weights

Recently, Li [16] introduced three kinds of single-hidden layer feed-forward neural networks with optimized piecewise linear activation functions and fixed weights, and obtained the upper and lower bound estimations on the approximation accuracy of the FNNs, for continuous function defined on bounded intervals. In the present paper, we point out that there are some errors both in the definitions of the FNNs and in the proof of the upper estimations in [16]. By using new methods, we also give right approximation rate estimations of the approximation by Li’s neural networks.     

On the Toughness of Cycle Permutation Graphs

Motivated by the conjectures in [11], we introduce the maximal chains of a cycle permutation graph, and we use the properties of maximal chains to establish the upper bounds for the toughness of cycle permutation graphs. Our results confirm two conjectures in [11].     

Elementary density bounds for self-similar sets and application

Falconer[1] used the relationship between upper convex density and upper spherical density to obtain elementary density bounds for s-sets at H S-almost all points of the sets. In this paper, following Falconer[1], we first provide a basic method to estimate the lower bounds of these two classes of set densities for the self-similar s-sets satisfying the open set condition （OSC）, and then obtain elementary density bounds for such fractals at all of their points. In addition, we apply the main results to the famous classical fractals and get some new density bounds.     

Thue inequalities with a small number of primitive solutions

Several upper bounds are known for the numbers of primitive solutions (x; y) of the Thue equation (1) j F(x; y) j = m and the more general Thue inequality (3) 0 < j F(x; y) j m. A usual way to derive such an upper bound is to make a distinction between "small" and "large" solutions, according as max( j x j ; j y j ) is smaller or larger than an appropriate explicit constant Y depending on F and m; see e.g. [1], [11], [6] and [2]. As an improvement and generalization of some earlier results we give in Section 1 an upper bound of the form cn for the number of primitive solutions (x; y) of (3) with max( j x j ; j y j )Y0 , wherec 25 is a constant and n denotes the degree of the binary form F involved (cf. Theorem 1). It is important for applications that our lower bound Y0 for the large solutions is much smaller than those in [1], [11], [6] and [4], and is already close to the best possible in terms of m. ByusingTheorem1 we establish in Section 2 similar upper bounds for the total number of primitive solutions of (3), provided that the height or discriminant of F is suficiently large with respect to m (cf. Theorem 2 and its corollaries). These results assert in a quantitative form that, in a certain sense, almost all inequalities of the form (3) have only few primitive solutions. Theorem 2 and its consequences are considerable improvements of the results obtained in this direction in [3], [6], [13] and [4]. The proofs of Theorems 1 and 2 are given in Section 3. In the proofs we use among other things appropriate modifications and refenements of some arguments of [1] and [6].     

Tight and 0-tight polyhedral embeddings of surfaces

In [1] T. Banchoff has studied the problem of high condimensional tight polyhedral embeddings of closed surfaces into Euclidean space. He gave an upper bound for the essential codimension depending on the Euler characteristic of the surface. In [1] and [5] he proved that this bound is attained in some cases and that it is not attained for the Klein bottle. In the present paper we show that this bound is sharp in any case (except the Klein bottle) and that for each surface there exist tight substantial embeddings into Euclidean space of arbitrary dimension up to the Banchoff upper bound. The proof depends essentially on the Heawood map color theorem proved by G. Ringel and J.W.T. Youngs. In addition we get similar results for tight and 0-tight embeddings of surfaces with boundary where it may be remarkable that in case of tight surfaces with one boundary component the Banchoff upper bound can be improved.     

几类矩阵范数之间的关系

1 引言 [1]中,讨论了C~(m×n)上的矩阵A的L_p范数/A/_p=(∑/a_(ij)/~p)和l_p算子范数‖A‖_p= max/AX/_p1』之间的关系,得到了下面的不等式: ‖A‖_p≤μ_p(n)/A/_p, ‖A‖_p≤μ_q(m)/A/_p, (1.1) 这里     

Equilibrium problems with lower and upper bounds

In this paper, we obtain some existence results of equilibrium problems with lower and upper bounds by employing a fixed-point theorem due to Ansari and Yao [1] and Ky Fan Lemma [2], respectively. Our results give answers to the open problem raised by Isac, Sehgal and Singh [3].