arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1707.07549math.DG
收藏

四维空间中相对differential geometry的Bonnet型定理

Bonnet's type theorems in the relative differential geometry of the 4-dimensional space

Stylianos Stamatakis, Ioannis Kaffas

摘要:

我们在$\mathbb{R}^4$的相对微分几何框架下处理超曲面。我们考虑了$\mathbb{R}^4$中的一个超曲面$\varPhi$,其位置向量场$\vect{x}$被相对归一化$\vect{y}$相对归一化.则$\vect{y}$也是超曲面$\varPhi_μ$的单参数族$\mathcal{F}$的每个成员与位置向量场$\vect{x}_μ= \vect{x} + μ\, \vect{y}$的相对正规化,其中$μ$是实常数。我们称每个超曲面$\varPhi_μ\in \mathcal{F}$相对平行于$\varPhi$。这种考虑包括仿射微分几何的欧几里得超曲面和Blaschke超曲面。本文利用$\varPhi$的相对平均曲率函数和“相对距离”$μ$来表示相对平行于$\varPhi$的超曲面$\varPhi_μ$的相对平均曲率函数。然后证明了几个Bonnet型定理。更精确地说,我们证明了如果$\varPhi$的两个相对平均曲率函数都是常数,那么至少存在一个相对平行的超曲面具有一个常数的相对平均曲率函数。

英文摘要:

We deal with hypersurfaces in the framework of the relative differential geometry in $\mathbb{R}^4$. We consider a hypersurface $\varPhi$ in $\mathbb{R}^4$ with position vector field $\vect{x}$ which is relatively normalized by a relative normalization $\vect{y}$. Then $\vect{y}$ is also a relative normalization of every member of the one-parameter family $\mathcal{F}$ of hypersurfaces $\varPhi_μ$ with position vector field $\vect{x}_μ= \vect{x} + μ\, \vect{y}$, where $μ$ is a real constant. We call every hypersurface $\varPhi_μ\in \mathcal{F}$ relatively parallel to $\varPhi$. This consideration includes both Euclidean and Blaschke hypersurfaces of the affine differential geometry. In this paper we express the relative mean curvature's functions of a hypersurface $\varPhi_μ$ relatively parallel to $\varPhi$ by means of the ones of $\varPhi$ and the "relative distance" $μ$. Then we prove several Bonnet's type theorems. More precisely, we show that if two relative mean curvature's functions of $\varPhi$ are constant, then there exists at least one relatively parallel hypersurface with a constant relative mean curvature's function.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑