ON SYMMETRIC SCALAR CURVATURE ON

1.IntroductionGivenacontinuousfunctionRonthestandardsphereS',itisaninterestingproblemwhetherRcanbethescalarcurvatureofsomemetricgwhichispointwiseconformaltothestandardmetricgoonS2.Ifwesetg~e"go,whereuisafunctiononS',theproblemisequivalenttothesolvabilityofthefollowingPDE:--A..u 2--Re"=0,onS2.(l'1)KazdanandWarner[9]pointedoutthatitmaybeinsolvable.Inthelastfewyears,alotofworkhasbeendonetosolveproblem(l.l),especiallywhenRpossessessomekindsofsymmetries.AfterthepioneerworkduetoMoser[lo]forthe…     

一类中立型方程的正解

本文研究具有正负系数的中立型微分方程，分别得到了这类方程存在和不存在正解的充分条件，并建立了不存在正解的比较定理。     

EXISTENCE OF POSITIVE SOLUTIONS TO QUASI-LINEAR EQUATION INVOLVING CRITICAL SOBOLEV-HARDY EXPONENT

This paper is concerned with the quasi-linear equation with critical SobolevHardy exponent where Ω RN(N ≥ 3) is a smooth bounded domain, 0 ∈Ω, 0 ≤ s ＜ p, 1 ＜ p ＜ N,p* (s) :=p(N- s)/N-p is the critical Sobolev-Hardy exponent, λ＞ 0,p ≤ r ＜ p* ,p* := Np/N-p is the critical Sobolev exponent, μ＞ 0, 0 ≤ t ＜ p, p ≤ q ＜ p* (t) = P(N-t)/N-p.The existence of a positive solution is proved by Sobolev-Hardy inequality and variational method.     

ON THE EXISTENCE OF POSITIVE SOLUTIONS OF AN ELLIPTIC BOUNDARY VALUE PROBLEM ON THE EXISTENCE OF POSITIVE SOLUTIONS OF AN ELLIPTIC BOUNDARY VALUE PROBLEM

i. Introduction and the Main TheoremIn this paper, we consider the elliptic boundary value problemwhere fi C RN is a bounded domain with smooth boundary off, f: R - R satisfieslocally Lipschitz condition and f(0) 2 0. By a solution u of (1.l) we mean a c…     

标量曲率Finsler空间与Finsler度量的射影变换

本文研究了与一个Ricci平坦Finsler空间或一个常曲率Finsler空间射影相关的标量曲率Finsler空间．我们给出了这种标量曲率Finsler空间成为常曲率空间的充分必要条件.特别地，我们给出了射影平坦Finsler空间具有常曲率的条件．     

A COMPLETE METRIC OF POSITIVE CURVATURE ON R~n AND EXISTENCE OF CLOSED GEODESICS

ＡＣＯＭＰＬＥＴＥＭＥＴＲＩＣＯＦＰＯＳＩＴＩＶＥＣＵＲＶＡＴＵＲＥＯＮＲ~ｎＡＮＤＥＸＩＳＴＥＮＣＥＯＦＣＬＯＳＥＤＧＥＯＤＥＳＩＣＳ￥ＺＨＵＤＡＸＩＮ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，ＴｉａｎｊｉｎＵｎｉｖｅｒｓｉｔｙｌＴｉａｎｊ?..     

关于一类广义Ramanujan-Nagell方程的正整数解

本文研究了一类广义Ramanujan-Nagell方程有正整数解的条件.利用二次域中的重要理论,给出了一个典型的Ramanujan-Nagell方程的所有正整数解,推广了文献[1]和[2]的结果.     

高阶非线性差分方程的正解

本文讨论了一类奇数阶非线性中立型差分方程,获得了正解存在的充要条件和比较定理．     

POSITIVE PERIODIC SOLUTIONS OF FIRST AND SECOND ORDER ORDINARY DIFFERENTIAL EQUATIONS

In this paper the existence results of positive ω-periodic solutions are obtained forsecond order ordinary differential equation-u"(t)=f(t,u(t)) (t∈R), and also for firstorder ordinary differential equation u"(f)=f(t,u(t)) (t∈R), where f: R×R~ →Ris a continuous function which is ω-periodic in t. The discussion is based on the fixedpoint index theory in cones.     

中立型时滞差分方程的振性与正解存在性

本文研究了一类中立型时滞差分方程的振动性和正解存在性，获得了该方程所有解振动的“Sharp”条件及存在正解的一个充分条件．     

具有强迫项的Liénard方程解的有界性

讨论了具有强迫项的Liénard方程     

矩阵方程X-A*XqA=I(0＜q＜1)Hermite正定解的扰动分析

首先证明了非线性矩阵方程X-A~*X~qA=I(0相似文献   

POSITIVE PERIODIC SOLUTIONS OF NONLINEAR FUNCTIONAL DIFFERENCE EQUATION

Using the Krasnoselskii's fixed point theorem, the existence of positive periodic solutions to a class of nonlinear functional difference equations is studied in this paper. Some sufficient conditions for the existence of positive periodic solutions are presented.     

ON THE EXISTENCE OF POSITIVE SOLUTIONS OF AN ELLIPTIC BOUNDARY VALUE PROBLEM

Using variational method, the authors get an existence result for positive solutions of a superlinear elliptic boundary value problem without assuming the P.S. condition. To prove the results in this paper, the authors adopt the method of gradient flow and use a new class of truncation functions. Project supported by the National Natural Science Foundation of China and the Research Fund for the Doctoral Program of Higher Education of China.     

非线性特征值问题的正解

本文着重考察非线性特征值问题u"+λg(t)f(u)=0, 0相似文献   

EXISTENCE AND UNIQUENESS OF POSITIVE SOLUTIONS TO A CLASS OF SEMILINEAR ELLIPTIC SYSTEMS

In this paper an existence and uniqueness theorem of positive solutions to a class of semilinear elliptic systems is proved. Also, a necessary condition for the existence of the positive solution is obtained. As the application of the main theorem, two examples are given.     

高维常平均曲率超曲面的数量曲率的空隙

本文证明了当高维球面中闭常平均曲率超曲面Ｍ＾ｎ的平均曲率│Ｈ│＜Ｃ（ｎ）时，若Ｍ的数量曲率Ｒ为常数，则Ｒ不属于［ａ（ｎ，Ｈ），ａ（ｎ，Ｈ）＋ｎ／４），其中ａ（ｎ，Ｈ）＝ｎ（ｎ－９／４）＋ｎ＾２（ｎ－２）／２（ｎ－１）Ｈ＾２－ｎ（ｎ－２）／２（ｎ－１）√ｎ＾２Ｈ＾４＋４（ｎ－１）Ｈ＾２。     

ON HERMITIAN POSITIVE DEFINITE SOLUTIONS OF MATRIX EQUATION X-A^＊X^-2 A=I

The Hermitian positive definite solutions of the matrix equation X-A^＊X^-2 A=I are studied. A theorem for existence of solutions is given for every complex matrix A. A solution in case A is normal is given. The basic fixed point iterations for the equation are discussed in detail. Some convergence conditions of the basic fixed point iterations to approximate the solutions to the equation are given.     

一类矩阵方程的正交对称解及其最佳逼近

1引言设Rn×m表示所有n×m实矩阵集合,I表示单位矩阵,AT表示矩阵A的转置矩阵, ORn×n={P|PTP=I)表示列正交矩阵集,SORn×n={P|PT=P,P2=I}表示对称正交对称矩阵集．如无特别说明,本文中的矩阵P均指这类对称正交对称矩阵．在Rn×m上定义内积为     

CONFORMAL DEFORMATION OF COMPLETE SURFACE WITH NEGATIVE CURVATURE

ＣＯＮＦＯＲＭＡＬＤＥＦＯＲＭＡＴＩＯＮＯＦＣＯＭＰＬＥＴＥＳＵＲＦＡＣＥＷＩＴＨＮＥＧＡＴＩＶＥＣＵＲＶＡＴＵＲＥＺＨＯＵＤＥＴＡＮＧＭａｎｕｓｃｒｉｐｔｒｅｃｅｉｖｅｄＯｃｔｏｂｅｒ３１，１９９４．ＲｅｖｉｓｅｄＡｕｇｕｓｔ３０，１９９５．Ｄ...