各向异性次Laplace算子和拟p-次Laplace算子的Picone恒等式及其应用

本文首次把欧氏空间中的各向异性Laplace算子和拟p-Laplace算子分别引入到Heisenberg群Hn上,分别称为各向异性次Laplace算子和拟p-次Laplace算子,不仅建立它们相对应的Picone恒等式,而且还给出这些Picone恒等式的应用,从而把欧氏空间中的相关结果推广到Heisenberg群H~n上.     

几个关于Mercier恒等式的推广

本文建立了几个包含Gauss二项系数的恒等式，这些结果推广了几个Mercier的结果。     

关于包含Hermite-Laguerre多项式的恒等式

通过讨论一类函数的高阶导数 ,建立了一些包含 Hermite-Laguerre多项式的恒等式 ,推广了著名的 Cauchy-Sheehan组合恒等式 .     

关于有限形式的Hilbert不等式

利用一个积分恒等式部分地解决有限形式Hilbert不等式中常数C（p,q）的渐近性态问题.     

一个Ramanujan Tau函数的新表达式

通过对Ramanujan Tau函数的研究,并借助Ewell的一个关于q-级数的恒等式结果,发现了关于Ramanujan Tau函数的生成函数的恒等式,该恒等式中含有两类重要的算术函数,即表正整数为若干三角数的和的表法数及表正整数为若干平方数的和的表法数.从而得到了一个关于Ramanujan Tau函数新的显式表达式.最后作为结果的应用,该文还给出了一个关于Ramanujan Tau函数新的简洁同余恒等式.     

关于包含Hermite—Laguerre多项式的恒等式

通过讨论一类函数的高阶导数,建立了一些包含Hermite-Laguerre多项式的恒等式,推广了名的Cauchy-Sheehan组合恒等式。     

t次正规环的一个恒等式定理及其应用

一个适合 t 正规多项式的环叫做 t 次正规环。本文得到一个关于 t 次正规环的恒等式定理,并在此定理基础上得出交换环的另一些恒等式,它们是著名的环的交换性问题的一些结果或类似的结果。     

大卫星恒等式的组合证明

以Np表示1到p的自然数集合,Fn(1,2,…,p)表示元素取自Np的有序n元组的集合,Fnn1n2…np1 2…p表示所有含n1个1,n2个2,…,np个p(n1 n2 … np=n)的有序n元组的集合.通过组合分析法可以证明这两类n元组集合的性质,进而给出"大卫星恒等式"及一些组合恒等式的组合性证明.     

杨辉三角形的若干性质

研究了杨辉三角中的D av id星恒等式,给出了n阶星恒等式的定义,证明了n(n 3)阶星恒等式的存在性,并且给出了构造n阶星恒等式的方法.     

函数Sp(n2)与Sp(n)的关系

对于任意正整数n,设幂p的原数函数Sp(n)定义为Sp(n)=min{m:pn|m!},其中p为素数.本文目的是运用初等方法研究函数Sp(n2)与Sp(n)之间的关系,并得到一个有趣的恒等式.     

关于一类向量场的Picone恒等式和Hardy不等式1

本文给出了构成Baouendi-Grushin算子 的向量场的Picone恒 式,由此导出了Hardy不等式.已有文献中得到的不等式成为本文结果的特殊情形。     

Geodesic vector fields and Eikonal equation on a Riemannian manifold

In this paper, we study the impact of geodesic vector fields (vector fields whose trajectories are geodesics) on the geometry of a Riemannian manifold. Since, Killing vector fields of constant lengths on a Riemannian manifold are geodesic vector fields, leads to the question of finding sufficient conditions for a geodesic vector field to be Killing. In this paper, we show that a lower bound on the Ricci curvature of the Riemannian manifold in the direction of geodesic vector field gives a sufficient condition for the geodesic vector field to be Killing. Also, we use a geodesic vector field on a 3-dimensional complete simply connected Riemannian manifold to find sufficient conditions to be isometric to a 3-sphere. We find a characterization of an Einstein manifold using a Killing vector field. Finally, it has been observed that a major source of geodesic vector fields is provided by solutions of Eikonal equations on a Riemannian manifold and we obtain a characterization of the Euclidean space using an Eikonal equation.     

Harmonicity of vector fields on the oscillator groups with neutral signature

In this paper, we mainly investigate curvature properties and harmonicity of invariant vector fields on the four-dimensional Oscillator groups endowed with three left-invariant pseudo-Riemannian metrics of signature (2,2). We determine all harmonic vector fields, vector fields which define harmonic maps and the vector fields which are critical points for the energy functional restricted to vector fields of the same length.     

SMOOTH CLASSIFICATION AND LINEARIZATION OF HYPERBOLIC VECTOR FIELDS ON R~3

This paper is devoted to studying smooth normal form theory of hyperbolic vector fields. As a continuation of our previous work on smooth classification and linearization of vector fields near a hyperbolic singular point,in this paper,we deal with the case of hyperbolic vector fields on R3 by examining all possible resonant classes.     

Complex structures adapted to smooth vector fields

In this paper we study the flat geometry and real dynamics of meromorphic vector fields on compact Riemann surfaces. Necessary and sufficient conditions to assert the existence of meromorphic vector fields with prescribed singularities are given. A characterization of the real dynamics of meromorphic vector fields is also given. Several explicit examples of meromorphic vector fields, using singular flat metrics, are provided. Received: 12 June 1998 / Accepted: 28 September 2000 / Published online: 18 January 2002     

Strongly and weakly affine vector fields on Finsler manifolds

In this paper, we investigate the affine vector fields on both compact and forward complete Finsler manifolds. We first give definitions of the affine transformation and the affine vector field. Unexpectedly, we find two kinds of affine fields, which are named as the strongly and weakly affine vector fields. Based on these definitions, we prove some rigidity theorems of affine fields on compact and forward complete Finsler manifolds.     

Projective vector fields on Finsler manifolds

In this paper, we give the equation that characterizes projective vector fields on a Finsler manifold by the local coordinate. Moreover, we obtain a feature of the projective fields on the compact Finsler manifold with non-positive flag curvature and the non-existence of projective vector fields on the compact Finsler manifold with negative flag curvature. Furthermore, we deduce some expectable, but non-trivial relationships between geometric vector fields such as projective, affine, conformal, homothetic and Killing vector fields on a Finsler manifold.     

Polynomial vector fields on the torus

In this paper it is shown that the structurally stable polynomial vector fields on the torusT ², with singularities, are open and dense in the set of such vector fields. Many kinds of distinct dynamical phenomena are also presented by a list of examples including the Cherry flows. The above result works for analytical vector fields onT ² with the same proof.     

FIVE LIMIT CYCLES TO A CLASS OF SYSTEMS IN R~3

In this paper, a bridge between near-homogeneous and homogeneous vector fields in R 3 is found. By the relationship between homogeneous vector fields and the induced tangent vector fields of two-dimensional manifold S 2 , we prove the existence of at least 5 isolated closed orbits for a class of n + 1 (n ≥ 2) systems in R 3 , which are located on the five invariant closed cones of the system.     

与广义Baouendi-Grushin向量场相联系的Hardy不等式及其应用

本文建立一类与广义Baouendi—Grushin向量场联系的Hardy不等式．采用的技巧是延伸欧氏空间上的散度定理推出的基本积分不等式和选定适当的向量场．Hardy不等式相应的最佳常数也得到证明．本文结果包括了已有广义Baouendi-Grushin向量场的Hardy不等式．作为应用，讨论了由Baouendi-GrusMn向量场构成一退化次椭圆算子的一些性质和刻画了这类向量场构成的非线性算子的一个正解．