双曲Yamabe流的精确解

得到了双曲Yamabe流的一些精确解.第一类解是具有初始度量为Einstein的解,第二类解是具有轴对称的解.最后,作为这种流的特殊解,定义了稳定双曲Yamabe孤子,而且得到了这种孤子解所满足的方程.     

一类非线性双曲型发展方程的孤子解

研究了一类非线性发展方程.首先在无扰动情形下,利用待定函数和泛函同伦映射方法得到了非扰动发展方程的孤子精确解和扰动方程的任意次近似行波孤子解.接着引入一个同伦映射,并选取初始近似函数,再用同伦映射理论,依次求出非线性双曲型发展扰动方程孤子解的各次近似解析解.再利用摄动理论举例说明了用该方法得到的近似解析解的有效性和各次近似解的近似度.最后,简述了用同伦映射方法得到的近似解的意义,指出了用上述方法得到的各次近似解具有便于求解、精度高等优点.     

Riemann曲面上耗散双曲几何流的整体经典解

基于Einstein方程和Hamilton Ricci流为背景,孔德兴和刘克峰最近提出了耗散双曲几何流的概念.考虑耗散双曲几何流Cauchy问题,证明了对于任意给定的初始度量,总存在初始的对称张量,使得经典解整体存在,并且对应的曲率保持一致有界.否则,其经典解会在有限时间内破裂.     

高维弱扰动破裂孤子波方程行波解

研究了一类高维弱扰动破裂孤子波方程.首先讨论了对应的典型破裂孤子波方程, 利用待定系数投射方法得到了孤子波精确解.再利用泛函分析和摄动理论得到了原弱扰动破裂孤子波方程的孤子行波渐近解.最后, 举出例子说明了用该方法得到的弱扰动破裂孤子波方程的行波渐近解具有简捷、有效和较高精度的优点.     

推广的（2＋1）维浅水波方程的精确解及其混沌行为

利用Riccati方程映射法和变量分离法,得到了推广的（2＋1）维浅水波系统的变量分离解（包括孤波解、周期波解和有理函数解）.根据得到的孤波解,构造出了方程的单孤子和双孤子结构,研究了孤子的混沌行为.     

非等谱广义耦合非线性Schrdinger方程的局部化孤立波(英文)

利用Hirota双线性方法求解了一个非等谱广义耦合非线性Schr(o|¨)dinger方程,得到它的N-孤子解.其中单孤子可以描述一个任意大振幅且具有时间和空间双重局部性的孤立波,这种特征与所谓的"怪波"相一致.此外,借助于图像描述了二孤子的相互作用.     

广义高维Klein-Gordon强迫扰动方程的孤子解

利用同伦映射方法研究了一类非线性广义强迫扰动Klein-Gordon方程.首先利用双曲正切待定系数法求得了无扰动项典型方程的孤子解.然后利用同伦映射原理得到了强迫扰动Klein-Gordon方程的任意次近似孤子解.最后叙述了得到的近似孤子解是一个解析展开式,还能对它进行解析运算.这对使用简单的模拟方法得到的近似解是达不到的.     

高维扰动破裂孤子方程行波解的渐近解法

本文研究一类高维扰动破裂孤子方程.首先讨论对应典型的破裂方程,利用投射方法得到孤子精确行波解.再利用修改的广义投射近似方法得到扰动破裂孤子方程的行波渐近解.     

(2+1)维耗散长波方程的新精确解及其演化

在Mathematica符号计算软件的帮助下,利用拓展的G'/G展开法和变量分离法,得到(2+1)维耗散长波方程的新精确解,通过选取合适的函数,可以构造出dromion解、Solitoff解、周期孤波解等,并进一步研究孤子随时间的演化过程.     

广义Broer-Kaup-Kupershmidt孤子方程的拟周期解

该文从新谱问题出发,得到一个新的(2+1)-维广义Broer-Kaup-Kupershmidt孤子方程在Lax对非线性化下被分解成可积的常微分方程.接着,给出了一个有限维Hamilton系统并且证明在Liouville意义下是完全可积的.通过引进Abel-Jacobi坐标把Hamilton流进行了拉直,借助Riemannθ函数得到了(2+1)-维Broer-Kaup-Kupershmidt孤子方程的拟周期解.     

Finite Energy Solutions to the Yamabe Equation

We prove the existence of positive, finite energy solutions to the Yamabe equation

Estimations uniformes pour l'équation de Yamabe en dimensions 5 et 6

We give some a priori estimates for Yamabe equation on Riemannian manifold in dimensions 5 and 6. In dimension 5 we present an inequality of type sup×inf. In dimension 6, we have an estimate if we assume that the infima of the solutions are uniformly bounded below by some positive constant.     

Compactness of solutions to the Yamabe problem. III

For a sequence of blow up solutions of the Yamabe equation on non-locally conformally flat compact Riemannian manifolds of dimension 10 or 11, we establish sharp estimates on its asymptotic profile near blow up points as well as sharp decay estimates of the Weyl tensor and its covariant derivatives at blow up points. If the Positive Mass Theorem held in dimensions 10 and 11, these estimates would imply the compactness of the set of solutions of the Yamabe equation on such manifolds.     

The contact Yamabe flow on K-contact manifolds

We use the contact Yamabe flow to find solutions of the contact Yamabe problem on K-contact manifolds.     

Existence and concentration of positive solutions for a super-critical fourth order equation

In this paper we investigate the problem of existence of solutions for a super-critical fourth order Yamabe type equation and we exhibit a family of solutions concentrating at two points, provided the domain contains one hole and we give a multiplicity result if we are given multiple holes.     

On the $h$-Almost Yamabe Soliton

We introduce the concept $h$-almost Yamabe soliton which extends naturally the almost Yamabe soliton by Barbosa-Ribeiro and obtain some rigidity results concerning $h$-almost Yamabe solitons. Some condition for a compact $h$-almost Yamabe soliton to be a gradient soliton is also obtained. Finally, we give some characterizations for a special class of gradient $h$-almost Yamabe solitons.     

Global existence and regularity of solutions to a system of nonlinear Maxwell equations

We consider the model that has been suggested by Greenberg et al. (Physica D 134 (1999) 362-383) for the ferroelectric behavior of materials. In this model, the usual (linear) Maxwell's equations are supplemented with a constitutive relation in which the electric displacement equals a constant times the electric field plus an internal polarization variable which evolves according to an internal set of nonlinear Maxwell's equations. For such model we provide rigorous proofs of global existence, uniqueness, and regularity of solutions. We also provide some preliminary results on the long-time behavior of solutions. The main difficulties in this study are due to the loss of compactness in the system of Maxwell's equations. These results generalize those of Greenberg et al., where only solutions with TM (transverse magnetic) symmetry were considered.     

On Nonlinear Hyperbolic Functional Differential Equations

In this paper, existence of weak solutions of second order evolution equations is proved and some properties of the solutions are shown. The results are applied to higher order nonlinear hyperbolic functional differential equations.     

Discrete quasi-Einstein metrics and combinatorial curvature flows in 3-dimension

Motivated by the definition of combinatorial scalar curvature given by Cooper and Rivin, we introduce a new combinatorial scalar curvature. Then we define the discrete quasi-Einstein metric, which is a combinatorial analogue of the constant scalar curvature metric in smooth case. We find that discrete quasi-Einstein metric is critical point of both the combinatorial Yamabe functional and the quadratic energy functional we defined on triangulated 3-manifolds. We introduce combinatorial curvature flows, including a new type of combinatorial Yamabe flow, to study the discrete quasi-Einstein metrics and prove that the flows produce solutions converging to discrete quasi-Einstein metrics if the initial normalized quadratic energy is small enough. As a corollary, we prove that nonsingular solution of the combinatorial Yamabe flow with nonpositive initial curvatures converges to discrete quasi-Einstein metric. The proof relies on a careful analysis of the discrete dual-Laplacian, which we interpret as the Jacobian matrix of curvature map.     

Sur quelques problèmes de courbure scalaire

In this article we prove, among other things, some results about two problems which are the subject of announces these last decades: (1) the compactness of the set of the solutions of the Yamabe equation on a compact Riemannian manifold, (2) a generalization of a result of the author which is necessary to solve the Yamabe problem, when 2ω?n−6.