Apollonian等距与Mbius变换

设D是~2中至少包含三个边界点的单连通区域,对任意x,y∈D,α_D(x,y)表示D中关于x,y两点的Apollonian度量．1998年A．F．Beardon猜测：若f：D→D是Apollonian等距映射,则f必是D上的Mbius变换．在该文中作者对D是圆的情况肯定并证明了A．F．Beardon的上述猜想．     

Apollonian等距与Mobius变换

设D是R²中至少包含三个边界点的单连通区域, 对任意x, y∈ D, aD(x, y)表示D中关于x, y两点的Apollonian度量．1998年A. F. Beardon猜测: 若f: D→ D是Apollonian等距映射,则f必是D上的Mobius变换.在该文中作者对D是圆的情况肯定并证明了A. F. Beardon的上述猜想     

Banach 空间中广义正交与度量投影

本文利用广义正交(“⊥”)这一工具,给出了在不自反的Banach空间中多值算子P为集值度量投影PL的充要条件是(i)P-1(0)=L(⊥),(ii)x∈X,y∈L,P(x y)=P(x) y,我们的结果推广了文[2]的在自反空间中且P为单值度量投影的相应结论;还得到了L(⊥)为线性子空间的充要条件是PL为有界线性算子;进而得到了L广义正交拓扑可补的充要条件是PL为有界线性算子,丰富了文[1,9]的结论.     

一致区域与拟双曲度量

设 D 是 R~n(n≥2)的真子区域.F.W.Gehving 与 B.G.Osgood 证明,D 是一致区域的充分必要条件是:存在常数 c 和 d,使得 k_D(x_1,x_2)≤cj_D(x_1,x_2)+d,(?)x_1,x_2∈D.本文证明,这个条件可减弱为:存在一常数 A,使得K_D(x_1,x_2)≤A·j_D(x_1,x_2),(?)x_1,x_2∈D.这里 K_D(x_1,x_2)为 D 中任意两点 x_1,x_2的拟双曲度量,j_D(x_1,x_2)=1/2log([|x_1-x_2|]/[d(x_1,(?)D)]+1)([|x_1-x_2|]/[d(x_2,(?)D)]+1),d(x,(?)D)为 x 到(?)D 的欧氏距离.     

关于（α，β）-度量的S-曲率

给出（α，β）-度量F=αФ（α，β）的S-曲率的计算公式．证得对一般的（α，β）-度量，当β为关于α长度恒定的Killing1-形式时，S=0．研究了Matsumoto-度量F=α^2／（α-β）和（α，β），度量F=α＋εβ＋κ（β^2／α）的S-曲率，证得S=0当且仅当β为关于α长度恒定的Killing1-形式．同时还得到这两类度量成为弱Berwald度量的充要条件,其中Ф（s）为光滑函数，α（y）=√aij（x）y^iy^j为黎曼度量，β（y）=bi（x）y^i为非零1-形式且ε，κ≠0为常数．     

局部LIPSCHJTZ型映射的G■TEAUX 可导性

设 X 和 y 是 Banach 空间,D 是 X 的子集,映射 F:D→Y 称为是 Lipschitz 型的,如果存在正常数 L,使得对任意的 x,y∈D,满足‖F(x)-F(y)‖≤L‖x-y‖;映射 F 称为是局部 Lipschitz 型的,如果对每个 α∈D,存在 α 的开邻域 N(α),使得 F     

序列覆盖的闭映射保持可度量性

设f:X→Y是连续的满映射. f称为序列覆盖映射,若{y})是Y中的收敛序列,则存在X中的收敛序列{xn},使得每一xn∈f-1(yn);f称为1序列覆盖映射,若对于每-y∈Y,存在x∈f-1(y),使得如果{yn}是Y中收敛于点y的序列,则有X中收敛于点x的序列{xn},使得每一xn∈f-1(yn).本文研究度量空间序列覆盖的闭映射之构造,否定地回答了Topology and its Applications上提出的一个问题.     

凸度量空间中非扩张映象的不动点定理

设X是一凸度量空间,并且它的每一直径趋于零的非空闭子集的逆减序列具有非空交的性质.本文证明了,如果X的非空闭子集K的自映象T满足不等式:d(Tx,Ty)≤ad(x,y) b{d(x,Tx) d(y,Ty)} c{d(x,Ty) d(y,Tx)},(?)x,y∈K其中0≤a<1,b≥0,c≥0,使得a c≠0且a 2b 3c≤1.则T在K中存在唯一不动点.     

关于(α,β) -度量的S -曲率

给出(α,β) -度量F=α\phi(β/α)的S -曲率的计算公式. 证得对一般的(α,β) -度量,当β为关于α长度恒定的Killing1 -形式时,S=0.研究了Matsumoto -度量F=α²/(α-β)和(α,α) -度量F=α+εβ+kβ²/α)的S -曲率, 证得S=0当且仅当β为关于α长度恒定的Killing1 -形式.同时还得到这两类度量成为弱Berwald度量的充要条件.其中\phi(s)为光滑函数,α(y)=\sqrt{a_ij(x)yⁱy^j}为黎曼度量,β(y)=b_i(x)yⁱ为非零1 -形式且ε,k≠ 0为常数.     

有向路和有向圈的控制集数

1引言设G=(V,E)为无向图．子集D (?)V(G)是无向图G的控制集,如果对于任意的y,∈V(G)-D,都存在x∈D,使xy∈E(G)．G的控制集D是G的分裂控制集,如果G中由V(G)-D导出的子图G〈V(G)-D〉是不连通的．G的一个控制集D是G的一个强(弱)控制集,若dG(x)≥d_G(y)(d_G(x)≤d_G(y)),其中d_G(x)表示G中与点x关联的边数．对于有向图H=(V,A),子集D(?)V(H)称为H的控制集,如果对于任意的y∈     

Caftan-Hartogs域上K(a)hler-Einstein度量与Bergman度量的等价

本文研究的是华罗庚域的特殊类型第二类Cartan-Hartogs域的不变Bergman度量与Kahler-Einstein度量的等价问题.引入一种与Bergman度量等价的新的完备的Kahler度量ωgλ,其Ricci曲率和全纯截取率具有负的上下界.然后应用丘成桐对Schwarz引理的推广证明ωgλ等价于Kahler-Einstein度量,从而得到了Bergman度量与Khhler-Einstein度量的等价,即丘成桐关于度量等价的猜想在第二类Cartan-Hartogs域上成立.     

The Equivalence of the Complete Einstein-Kahler Metric and the Bergman Metric on YIII

In this paper we give the proof about the equivalence of the complete Einstein- Kahler metric and the Bergman metric on Cartan-Hartogs domain of the third type. And we obtain the method of getting the equivalence of two metrics.     

第四类Caftan-Hartogs域上Bergman度量与Einstein-Kahler度量等价

In this paper,we discuss the invariaut complete metric on the Cartan-Hartogs domain of the fourth type.Firstly,we find a new invariant complete metric,and prove the equivalence between Bergman metric and the new metric;Secondly,the Ricci curvature of the new metric has the super bound and lower bound;Thirdly,we prove that the holomorphic sectional curvature of the new metric has the negative supper bound;Finally,we obtain the equivalence between Bergman metric and Einstein-Kahler metric on the Cartan-Hartogs domain of the fourth type.     

On Perturbation Stability of Metric Regularity

We introduce a measure of closeness for set-valued mappings from a metric space to a Banach space which allows to quantatively estimate the effect of perturbation of a set-valued mapping on its metric regularity and covering characteristics.     

Approximation of Metric Spaces by Partial Metric Spaces

Partial metrics are generalised metrics with non-zero self-distances. We slightly generalise Matthews' original definition of partial metrics, yielding a notion of weak partial metric. After considering weak partial metric spaces in general, we introduce a weak partial metric on the poset of formal balls of a metric space. This weak partial metric can be used to construct the completion of classical metric spaces from the domain-theoretic rounded ideal completion.     

The Metric of Large Deviation Convergence

We construct a metric space of set functions ( , d) such that a sequence {P _n} of Borel probability measures on a metric space ( , d*) satisfies the full Large Deviation Principle (LDP) with speed {a _n} and good rate function I if and only if the sequence converges in ( , d) to the set function e ^–I . Weak convergence of probability measures is another special case of convergence in ( , d). Properties related to the LDP and to weak convergence are then characterized in terms of ( , d).     

Products of Hyperbolic Metric Spaces

Let (X _i d _i ), i=1,2, be proper geodesic hyperbolic metric spaces. We give a general construction for a 'hyperbolic product' X ₁× _h X ₂ which is itself a proper geodesic hyperbolic metric space and examine its boundary at infinity.     

关于Fuzzy度量空间的一点注记

本文讨论了Ｆｕｚｚｙ度量空间（Ｘ，ｄ，Ｌ，Ｋ）中几种常用的Ｋ之间的关系及其具有的相应的度量性质。     

Quasivarieties of Metric Algebras

We introduce concepts of a continuous family of quasi-identities and of a continuous quasivariety. For continuous quasivarieties, a characterization theorem and an analog of the Birkhoff theorem on subdirect decomposition are proved. Also we point out the way of constructing examples of continuous quasivarieties and furnish the characterization of a relative congruence lattice of systems in the quasivarieties in question. Lastly, we re-prove the Hahn–Banach theorem on extension of a linear functional.