論ПОНТРЯГИН示性类,Ⅱ

<正> 前言 本文是[1]§§5,6中所述結果的詳細證明。 假定M是一個m維的可微分閉流形,是M的一個微分構造。對於而言,在M的各點的切面很自然地决定一個m歐氏空間叢。如果     

K(a)hler Manifolds with Almost Non-negative Ricci Curvature

Compact K(a)hler manifolds with semi-positive Ricci curvature have been investigated by various authors. From Peternell's work, if M is a compact K(a)hler n-manifold with semi-positive Ricci curvature and finite fundamental group, then the universal cover has a decomposition (M) ≌ X1 × … × Xm, where Xj is a Calabi-Yau manifold, or a hyperK(a)hler manifold, or Xj satisfies Ho(Xj,Ωp) = 0. The purpose of this paper is to generalize this theorem to almost non-negative Ricci curvature K(a)hler manifolds by using the Gromov-Hausdorff convergence. Let M be a compact complex n-manifold with non-vanishing Euler number. If for any ε ＞ 0, there exists a K(a)hler structure (Je,ge) on M such that the volume Volge(M) ＜ V, the sectional curvature |K(gε)| ＜ Λ2, and the Ricci-tensor Ric(gε)＞ -εgε, where ∨ and Λ are two constants independent of ε. Then the fundamental group of M is finite, and M is diffeomorphic to a complex manifold X such that the universal covering of X has a decomposition, (X) ≌ X1 × … × Xs, where Xi is a Calabi-Yau manifold, or a hyperK(a)hler manifold, or Xi satisfies Ho(Xi, Ωp) = {0}, p ＞ 0.     

UNIFORM ESTIMATES OF SOLUTIONS OF (δ)-EQUATION ON STEIN MANIFOLDS

By means of the Hermitian metric and Chern connection, Qiu [4] obtained the Koppelman-Leray-Norguet formula for (p, q) differential forms on an open set with C1 piecewise smooth boundary on a Stein manifold, and under suitable conditions gave the solutions of (δ)-equation on a Stein manifold. In this article, using the method of Range and Siu [5], under suitable conditions, the authors complicatedly calculate to give the uniform estimates of solutions of (δ)-equation for (p, q) differential forms on a Stein manifold.     

Gradient estimates of a nonlinear elliptic equation for the V -Laplacian

This paper studies gradient estimates for positive solutions of the nonlinear elliptic equation $$\begin{aligned} \Delta _V(u^p)+\lambda u=0,\quad p\ge 1, \end{aligned}$$on a Riemannian manifold (M, g) with k-Bakry–Émery Ricci curvature bounded from below. We consider both the case where M is a compact manifold with or without boundary and the case where M is a complete manifold.     

复Finsler流形上的Koppelman-Leray-Norguet公式

利用不变积分核(Berndtsson核),复Finsler度量和联系于Chern-Finsler联络的非线性联络,研究复Finsler流形上具有逐块光滑C~((1))边界的有界域上(p,q)型微分形式的积分表示,得到了(p,q)型微分形式的Koppelman-Leray-Norguet公式和■-方程的解．作为应用,利用复Finsler度量和联系于Chern-Finsler联络的非线性联络,给出了Stein流形上具有逐块光滑C~((1))边界的有界域上(p,q)型微分形式的Koppelman- Leray-Norguet公式以及■-方程的解,并且得到了Stein流形上实非退化强拟凸多面体上(p,q)型微分形式的积分表示式和■-方程的解．     

Estimation for jump processes in the tangent bundle of a Riemann manifold

A stochastic process is formulated in the tangent bundle of a Riemann manifold where the vector fibre portion of the process is a jump process. Since the tangent spaces change as the process in the base manifold evolves, it is necessary to define a jump process in the fibres of the tangent bundle with respect to the process in the base manifold. An estimation problem is formulated and solved for a process obtained from the jump process in the fibres of the tangent bundle where the observations include the process in the base manifold and the jump times. Since each fibre of the tangent bundle is a linear space, a suitable modification of some results for estimation in linear spaces can be used to solve the aforementioned estimation problem.Research supported by NSF Grants ENG 75-06562 and MCS 76-01695 and AFOSR Grant 77-3177.     

Geometric Estimates of the First Eigenvalue of (p,q)-elliptic Quasilinear System Under Integral Curvature Condition

Consider (M,g) as a complete, simply connected Riemannian manifold. The aim of this paper is to provide various geometric estimates in different cases for the first eigenvalue of (p,q)-elliptic quasilinear system in both Dirichlet and Neumann conditions on Riemannian manifold. In some cases we add integral curvature condition and maybe we prove some theorems under other conditions.     

MINIMAL SUBMANIFOLDS IN A RIEMANNIAN MANIFOLD OF QUASI CONSTANT CURVATURE

A Riemannian manifold V~m which admits isometric imbedding into two spaces V~(m+p)ofdifferent constant curvatures is called a manifold of quasi constant curvature.TheRiemannian curvature of V~m is expressible in the formand conversely.In this paper it is proved that if M~n is any compact minimal submanifoldwithout boundary in a Riemannian manifold V~(n+p)of quasi constant curvature,then∫_(M~u)(2-1/p)σ~2-[na+1/2(b-丨b丨)(n+1)]σ+n(n-1)b~2*丨≥0,where σ is the square of the norm of the second fundamental form of M~n When V~(n+p)is amanifold of constant curvature,b=0,the above inequality reduces to that of Simons.     

ON BOUNDEDNESS OF HARDY-LITTLEWOOD MAXIMAL FUNCTION OPERATOR ON RIEMANNIAN MANIFOLDS

The authors construct a complete Riemannian manifold such that its Hardy-Littlewood maximal function operator is unbounded in $L^p$ for some p > 1.     

复Finsler流形上的Hodge-Laplace算子

本文定义了强拟凸复Finsler流形上的Hodge-Laplace算子,并给出其水平部分的局部坐标表示．     

Krümmungseigenschaften transnormaler Mannigfaltigkeiten

In [6] ROBERTSON introduced the notion of a transnormal manifold as a generalization of a compact connected closed hypersurface of constant width in Euclidean space. This paper includes a detailed proof of the fact that the projection of a transnormal manifold on its space of normal planes is a covering map. Furthermore we prove the following generalization of a property of closed convex hypersurfaces of constant width: If two points p, q of a transnormal manifold have the same normal plane, then (for a suitable choice) the sum of the corresponding radii of principal curvature in direction of the common normal line is equal to the distance of p and q. Finally there are given examples of transnormal manifolds, which do not possess minimal total absolute curvature.

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Die vorliegende Arbeit stellt im wesentlichen die ersten Kapitel der von der Fakultät für Allgemeine Ingenieurwissenschaften der TU Berlin genehmigten Dissertation [9] dar.     

Beispiele homogener Mannigfaltigkeiten

Let X be a connected compact complex manifold. We call X a homogeneous manifold if there exists a complex Liegroup G of biholomorphic automorphisms of X such that for any two points p, qX there is a gG with: g(p)=q. We give some non-trivial examples of homogeneous manifolds. All examples are non-kaehlerian manifolds. Such examples have been given first by Iwasawa (as far as we know). The last section of this note contains a proposition, which shows that only very special non-semisimple Liegroups are able to act transitivily in the sense stated above, on a compact complex manifold. This is remarkable also in contrast to the semisimple case (cf. [3]).     

On a fiber bundle over a disk with the cantor set as a fiber

We construct a Pontryagin fiber bundle ξ = (N, p, S ¹), the total space N of which cannot be imbedded into any two-dimensional oriented manifold but can be imbedded into an arbitrary nonoriented two-dimensional manifold.     

Metrization and Semimetrization Theorems with Applications to Manifolds

This paper is a study of conditions under which a space with S₂ is metrizable, o-semimetrizable or semimetrizable. It is shown that: a wMN, w-space is metrizable if and only if it has S₂, a quasi--space is metrizable if and only if it is a pseudo wN-space with S₂, a separable manifold is metrizable if and only if it has S₂ with property (*), a perfectly normal manifold with q quasi-G ^* diagonal is metrizable and a separable manifold is a hereditarily separable metrizable if and only if it has -S₂.     

SOBOLEV INEQUALITY ON RIEMANNIAN MANIFOLDS

Let M be an n dimensional complete Riemannian manifold satisfying the doubling volume property and an on-diagonal heat kernel estimate. The necessary-sufficient condition for the Sobolev inequality ||f||q ≤Cn,,v,p,q(||(?)f||p ||f||p) (2 ≤p < q < ∞) is given.     

ON COMPLETE SPACE-LIKE SUBMANIFOLDS WITH PARALLEL MEAN CURVATURE VECTOR

§１．ＩｎｔｒｏｄｕｃｔｉｏｎＬｅｔＮｎ＋ｐｐｂｅａｎ（ｎ＋ｐ）－ｄｉｍｅｎｓｉｏｎａｌｃｏｎｎｅｃｔｅｄｐｓｅｕｄｏ－Ｒｉｅｍａｎｎｉａｎｍａｎｉｆｏｌｄｏｆｉｎｄｅｘｐ．ＩｆＮｎ＋ｐｐｉｓｃｏｍｐｌｅｔｅａｎｄｈａｓｃｏｎｓｔａｎｔｓｅｃｔｉｏｎ...     

Toric origami manifolds and multi-fans

The notion of a toric origami manifold, which weakens the notion of a symplectic toric manifold, was introduced by A. Cannas da Silva, V. Guillemin and A.R. Pires. They showed that toric origami manifolds bijectively correspond to origami templates via moment maps, where an origami template is a collection of Delzant polytopes with some folding data. Like a fan is associated to a Delzant polytope, a multi-fan introduced by A. Hattori and M. Masuda can be associated to an oriented origami template. In this paper, we discuss their relationship and show that any simply connected compact smooth 4-manifold with a smooth action of T ² can be a toric origami manifold. We also characterize products of even dimensional spheres which can be toric origami manifolds.     

七维透镜空间为不动点集的对合

设 ( M7+ k,T)是光滑闭流形上的一个非平凡光滑对合 ,它的不动点集为 7维透镜空间 L3( p) .本文首先计算了 L 3( p)上任意向量丛的全 Stiefel-Whitney类 ,其次讨论了 ( M7+ k,T)的存在性 ,在存在的情形下 ,给出了带对合的流形 ( M7+ k,T) 协边类 .     

Embeddability of smooth Cauchy-Riemann manifolds

Summary The main purpose of this paper is to give a sufficient condition for global embeddability of smooth Cauchy-Riemann manifolds (CR-manifolds) into complex manifolds with boundary. Namely, let M be a smooth CR-manifold of real dimension 2n – 1 and CR-dimension n – 1, where n 2, which is locally CR-embeddable into a complex manifold. Assume further that the Levi form of M is non-vanishing at each point. The main result of this paper is that such a CR-manifold is globally CR-embeddable into an n-dimensional complex manifold with boundary. Moreover if the Levi form has at each point of M eigenvalues of opposite signs, then M embeds into a complex manifold without boundary.This research is supported by a grant from Consiglio Nazionale delle Ricerche in Italy.     

拟常曲率Riemann流形中的伪脐点子流形

研究了拟常曲率Riemann流形中具有平行平均曲率向量的伪脐点子流形,得到了一个Simons型公式．