On the isometric minimal immersion into a euclidean space

We study the volume growth of the geodesic balls of a minimal submanifold in a Euclidean space. A necessary condition for the isometric minimal immersion into a Euclidean space is obtained. A classification of non-positively curved minimal hypersurfaces in a Euclidean space is given. This work is partially supported by the National Science Foundation of China     

到欧氏空间的等距极小浸入

本文研究了欧氏空间极小子流形的测地球的体积增长,给出了一个黎曼流形可等距极小浸入到欧氏空间的一个必要条件,并给出了具非正截曲率的欧氏空间极小超曲面的一个分类．     

COMPLETE SUBMANIFOLDS IN E~(n+p)WITH PARALLEL MEAN CURVATURE

This paper gives a pinching condition by which complete submanifolds in aEuclidean space can be classified completely.In particular,a characterization for acomplete submanifold in a Euclidean space to be totally umbilical is shown.     

CLASSIFICATION OF FINITE GROUPS GENERATED BY REFLECTIONS AND ROTATIONS

We classify finite groups generated by orthogonal transformations in a finite-dimensional Euclidean space whose fixed point subspace has codimension one or two. These groups naturally arise in the study of the quotient of a Euclidean space by a finite orthogonal group and hence in the theory of orbifolds.     

Some Bernstein-type rigidity theorems

We prove some Bernstein-type rigidity theorems for complete submanifolds in a Euclidean space and space-like submanifolds of a Lorentzian space. In particular, we obtain a Bernstein rigidity theorem for complete minimal submanifolds of arbitrary codimension in Euclidean space.     

Pointed helical submanifolds of euclidean space

A pointed helical submanifold of Euclidean space is defined and studied. In particular, complete pointed helical submanifolds of codimension 2 in a Euclidean space are classified.Dedicated to Professor N.K. Stephanidis on his 65th birthdayThis paper was supported by NON DIRECTED RESEARCH FUND, Korea Research Foundation, 1990 and partially supported by TGRC-KOSEF.     

Reconstruction from Line Integrals in Spaces of Constant Curvature

New reconstruction formula for the line integral transformation in Euclidean spaces is found. The general k-plane integral transform in Euclidean space is related to a totally geodesic integral transform for an arbitrary Riemannian space of constant curvature by means of a factorization property. Duality theorems for the totally geodesic transforms are stated.     

Conformal hypersurfaces with the same third fundamental form

We classify all hypersurfaces in a Euclidean space which allow conformal deformations, other than the ones obtained through conformal diffeomorphisms of the Euclidean space, preserving the third fundamental form.     

Planar sections of the quadric of Lie cycles and their Euclidean interpretations

All cycles (points, oriented circles, and oriented lines of a Euclidean plane) are represented by points of a three dimensional quadric in four dimensional real projective space. The intersection of this quadric with primes and planes are, respectively, two- and one-dimensional systems of cycles. This paper is a careful examination of the interpretation, in terms of systems of cycles in the Euclidean plane, of fundamental incidence configurations involving this quadric in projective space. These interpretations yield new and striking theorems of Euclidean geometry.     

Weighted Euclidean centers

This article addresses the derivation of a Euclidean center, which is defined as the point in decision space from which one can inscribe the largest sphere contained by the constraints. We extend this concept by introducing its weighted version, which we term the weighted Euclidean center. We show that by assigning weights to the different decision variables we can traverse the entire decision space. In addition, we show that the concept of a weighted Euclidean center and that of the achievement scalarizing function introduced by Wierzbicki are intimately related.     

高维欧氏空间中向量的外积

指出了对高维欧式空间中向量外积定义的不足,从几何空间中向量外积的几何描述入手,经过简洁的证明推导,重新提出了高维欧式空间中向量外积的定义,并得出了若干相关结论.     

The deformation of flat connections and affine manifolds

Geodesically complete affine manifolds are quotients of the Euclidean space through a properly discontinuous action of a subgroup of affine Euclidean transformations. An equivalent definition is that the tangent bundle of such a manifold admits a flat, symmetric and complete connection. If the completeness assumption is dropped, the manifold is not necessarily obtained as the quotient of the Euclidean space through a properly discontinuous group of affine transformations. In fact the universal cover may no longer be the Euclidean space. The main result of this paper states that if a flat connection of a bundle can be properly deformed into a metric connection then its Euler class vanishes. This is a partial result toward an old question of Chern.     

Embedding metric spaces in Euclidean space

In this paper, we give necessary and sufficient conditions for embedding a given metric space in Euclidean space. We shall introduce the notions of flatness and dimension for metric spaces and prove that a metric space can be embedded in Euclidean n-space if and only if the metric space is flat and of dimension less than or equal to n.     

On the volume functional of compact manifolds with boundary with constant scalar curvature

We study the volume functional on the space of constant scalar curvature metrics with a prescribed boundary metric. We derive a sufficient and necessary condition for a metric to be a critical point, and show that the only domains in space forms, on which the standard metrics are critical points, are geodesic balls. In the zero scalar curvature case, assuming the boundary can be isometrically embedded in the Euclidean space as a compact strictly convex hypersurface, we show that the volume of a critical point is always no less than the Euclidean volume bounded by the isometric embedding of the boundary, and the two volumes are equal if and only if the critical point is isometric to a standard Euclidean ball. We also derive a second variation formula and apply it to show that, on Euclidean balls and “small” hyperbolic and spherical balls in dimensions 3 ≤ n ≤ 5, the standard space form metrics are indeed saddle points for the volume functional.     

Isometric imbedding of a complete two-dimensional locally Euclidean manifold in a Euclidean space

In this article we consider the problem of isometric imbedding of a complete two-dimensional locally Euclidean manifold in a Euclidean space. For each of the possible topological types the corresponding minimal dimension of the extending Euclidean space is indicated. See [3].Translated from Matematicheskie Zametki, Vol. 13, No. 3, pp. 427–429, March, 1973.     

E~n中n维余弦定理和正弦定理的新证明

利用Grassmann代数的理论与方法,给出了n维欧氏空间En中n维单形第二余弦定理一种简单的证明.然后利用第二余弦定理给出了n维单形正弦定理一种新的简单证明.     

Hypersurfaces in and the variance of exit times for Brownian motion

Using the first exit time for Brownian motion from a smoothly bounded domain in Euclidean space, we define two natural functionals on the space of embedded, compact, oriented, unparametrized hypersurfaces in Euclidean space. We develop explicit formulas for the first variation of each of the functionals and characterize the critical points.

     

Brownian functionals on hypersurfaces in Euclidean space

Using the first exit time for Brownian motion from a smoothly bounded domain in Euclidean space, we define two natural functionals on the space of embedded, compact, oriented, unparametrized hypersurfaces in Euclidean space. We develop explicit formulas for the first variation of each of the functionals and characterize the critical points.

     

Metric Axiomatics of Euclidean Space @forename = A. A.

A version of axioms of Euclidean space based on a single initial notion, namely on the notion of distance, is considered. The notions of straight line and plane are introduced in terms of distance. Thus, Euclidean space is regarded as a metric space with metric satisfying the corresponding axioms. Bibliography: 3 titles.