第二类典型域的Busemann函数

本文给出了第二类典型城的 Ｂｕｓｅｍａｎｎ函数．证明了下面的定理：对 Ｒ-ＩＩ（ｐ）中通过０点的任一测地线其中Ｕ为 ｐ阶酉方阵,．则由ｒ决定的 Ｂｕｓｅｍａｎｎ函数为：．其中 为下列矩阵的对角元素：     

只有一个B—函数的完备黎曼流形

讨论了只有一个Ｂｕｓｅｍａｎｎ函数的完备非紧黎曼流形的几何拓扑性质。     

关于H. Wu问题

著名几何学家Ｈ．Ｗｕ在「４」中提出这样的问题：若一完备非紧的黎曼流形仅有两个符号相反的Ｂｕｓｅｍａｎｎ函数,则该流形的结构如何？本文在流形具非负Ｒｉｃｃｉ曲率或截曲率具下界的情况下部分地解决了这一问题。同时还讨论了流形在具非负曲率条件下有关的一些性质。     

On a Problem Proposed by Kartsatos

§１．ＩｎｔｒｏｄｕｃｔｉｏｎａｎｄＰｒｅｌｉｍｉｎａｒｉｅｓＬｅｔＸｂｅａｒｅａｌｒｅｆｌｅｘｉｖｅＢａｎａｃｈｓｐａｃｅｗｉｔｈｎｏｒｍａｎｄｎｏｒｍａｌｉｚｅｄｄｕａｌｉｔｙｍａｐｐｉｎｇＪ．Ａｓｕｓｕａｌ，ｗｅｓｕｐｐｏｓｅｔｈａｔｔｈｅｓｐ...     

非定常的热传导一对流问题的特征混合元法

１．引言 设 　 Ｒ２是足够光滑的有界区域，考虑非定常的热传导－对流方程的初边值问题： 问题Ｉ．求ｕ＝（ｕ１，ｕ２），ｐ，Ｔ满足：其中ｕ是流体的速度向量，ｐ为压力，Ｔ是温度，ｖ＞０是运动粘性系数，λ＞０是Ｇｒｏｓｈｏｆｆ数，ｊ＝（０，１）是二维向量，ｘ＝（ｘ１，ｘ２）． 非定常的热传导一对流方程是大气动力学中的一个重要的方程，这个方程组也称为强迫耗散的非线性系统方程组，其较Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程多了一个未知函数温度场，它与速度和压力之间存在着复杂的非线性关系．从热动力学可知，任何运动都会产生…     

R^N中的非线性退化椭圆方程粘性解的存在性

本文研究了Ｒ＾Ｎ中的非线性退化椭圆型方程Ｆ（Ｄｕ，Ｄ＾２ｕ）＋ｕｓ＝ｆ的非负粘性解的存在性，其中ｓ〉０，Ｆ满足某些关于ｐ的条件，本文在下面的条件下证明了存在性；１．ｓ〉ｐ－１，ｆ在无穷远处不需要增长条件；２．０〈ｓ≤ｐ－１，ｆ在无穷远处具有某种增长条件。     

紧Lie群上H~P（0＜P＜1）函数的临界阶Bochner－Riesz平均算子的有界性

本文利用尺度‖·‖＿（Ｈ（ｐ，∞））研究了一般紧Ｌｉｅ群上Ｈ￣ｐ函数的临界阶Ｂｏｃｈｎｅｒ－Ｒｉｅｓｚ平均算子的有界性，得到了如下结果：是（Ｈ￣ｐ，Ｈ（ｐ，∞））型的，并且其中Ｃ为与ｆ及Ｒ无关的常数。     

二维带形无界区域中Navier－Stokes方程整体吸引子及其维数估计

该文讨论二维无界带形区域中Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程其中Ω＝（０，ｄ）×Ｒ，ｄ＞０为一常数，ｕ与ｐ为未知量，其中ｕ＝（ｕ１，ｕ２）为速度场，ｐ表示压力．我们证明了当ｕ０∈Ｈ，ｆ∈Ｖ且ｆ［ｌｏｇ（ｅ＋｜ｘ｜２）］１／２∈Ｌ２（Ω）时，问题（Ｉ）在Ｈ中存在整体吸引子Ａ，它是的一个子集．对Ａ的Ｈａｕｓｄｏｒｆｆ维数与Ｆｒａｃｔａｌ维数我们也给出了估计．     

On Theorem of the “Mountain Impasse” Type

ＬｅｔＦ（ｕ），Ｇ（ｕ）ｂｅＣ１－ｆｕｎｃｔｉｏｎａｌｓｏｎａＨｉｌｂｅｒｔｓｐａｃｅＨａｎｄｓｕｐｕ∈ＨＦ（ｕ）＝∞．ＬｅｔＫｂｅａｃｏｍｐａｃｔｍｅｔｒｉｃｓｐａｃｅａｎｄｌｅｔＫｂｅａｎｏｎ－ｅｍｐｔｙｃｌｏｓｅｄｓｕｂｓｅｔ≠Ｋ，ｐ∈Ｃ（Ｋ；Ｈ）．ＤｅｎｏｔｅＦＲ＝｛ｕ∈Ｈ｜Ｆ（ｕ）Ｒ｝；　　　　　　ΦＲ＝｛ｐ∈Ｃ（Ｋ；ＦＲ）｜ｐ＝ｐｏｎＫ｝；ｃ（Ｒ）＝ｉｎｆｐ∈ΦＲｍａｘξ∈ＫＧ（ｐ（ξ））；ｃ０＝ｍａｘξ∈ＫＧ（ｐ（ξ））；Φ∞＝｛ｐ∈Ｃ（Ｋ；Ｈ）｜ｐ＝ｐｏｎＫ｝；…     

一类退缩椭园型方程弱解的正则性

本文得出一类形如：－Ｄｉｖ（ｇ（｜Ｄｕ｜）｜Ｄｕ｜＾ｐ－２Ｄｕ＋ｆ（ｘ,ｕ））＝Ｂ（ｘ,ｕ,Ｄｕ）在一定的条件下在Ｗ＾１．ｐ空间中的弱解的Ｈｏｌｄｅｒ连续性。     

Busemann functions and equilibrium measures in last passage percolation models

The interplay between two-dimensional percolation growth models and one-dimensional particle processes has been a fruitful source of interesting mathematical phenomena. In this paper we develop a connection between the construction of Busemann functions in the Hammersley last-passage percolation model with i.i.d. random weights, and the existence, ergodicity and uniqueness of equilibrium (or time-invariant) measures for the related (multi-class) interacting fluid system. As we shall see, in the classical Hammersley model, where each point has weight one, this approach brings a new and rather geometrical solution of the longest increasing subsequence problem, as well as a central limit theorem for the Busemann function.     

对称空间SU~*(2n)/sp(n)上的Busemann函数

Busemann函数在对完备Riemann流形上的拓扑与几何问题的研究中起作十分重要的作用。而显式求出一个域上的Busemann函数将有助于一些问题的解决。在本文中,我们显式求出了对称空间SU~*(2n)/sp(n)上的Busemann函数。     

經驗分佈對理論分佈的比值

<正> 設F(x)是隨機變数X的分佈函數,x_1,x_2,…,x_n是對X的n次相互獨立觀測的結果.將n個數據按照數值從小到大排列起來,以x_k代表其中的第k個,我們把原來的結果寫成     

Solution of a Busemann problem

We give a solution to the problem posed by Busemann which is as follows: Determine the noncompact Busemann G-spaces such that for every two geodesics there exists a motion taking one to the other. We prove that each of these spaces is isometric to the Euclidean space or to one of the noncompact symmetric spaces of rank 1 (of negative sectional curvature).     

第三类典型域的Busemann函数

本文利用第三类典型域测地线的矩阵形式算出其Busemann函数。     

阵的特征根的限界(Ⅱ)

<正> 本文是前文的续作,这里引用的記号与以前是一致的,例如(?)为实或复阵(?)的特征根,A~* 是 A 的共轭转置阵,(?)此外,还引用一些新的记号,(?)     

Locally G-homogeneous Busemann G-spaces

We present short proofs of all known topological properties of general Busemann G-spaces (at present no other property is known for dimensions more than four). We prove that all small metric spheres in locally G-homogeneous Busemann G-spaces are homeomorphic and strongly topologically homogeneous. This is a key result in the context of the classical Busemann conjecture concerning the characterization of topological manifolds, which asserts that every n-dimensional Busemann G-space is a topological n-manifold. We also prove that every Busemann G-space which is uniformly locally G-homogeneous on an orbal subset must be finite-dimensional.     

Geometry of manifolds with densities

We study the geometry of complete Riemannian manifolds endowed with a weighted measure, where the weight function is of quadratic growth. Assuming the associated Bakry–Émery curvature is bounded from below, we derive a new Laplacian comparison theorem and establish various sharp volume upper and lower bounds. We also obtain some splitting type results by analyzing the Busemann functions. In particular, we show that a complete manifold with nonnegative Bakry–Émery curvature must split off a line if it is not connected at infinity and its weighted volume entropy is of maximal value among linear growth weight functions.