arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2001.11417math.DG
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关于零子流形的中曲率

On the mean curvature of submanifolds with nullity

A. E. Kanellopoulou, Th. Vlachos

摘要:

本文研究了具有正相对零指数的等距浸入为圆柱的几何条件。在一类椭圆曲面上存在大量的非圆柱$n$维极小子流形,它们的指数为相对零$n-2$,由Dajczer和Florit \cite{DF2}充分描述.与此相反,我们证明了非最小$n$维子流形在空间形式的任何余维的局部圆柱,只要他们进行了全测地分布的秩$n-2\geq2,$这是包含在相对零度分布,使长度的中曲率向量场是常数沿每个叶片。维度$n=3$的情况是特殊的。证明了球面中存在满足上述性质的三维椭圆子流形。实际上,我们把三维子流形参数化为欧几里得空间中第一曲率椭圆处处为圆,第二曲率椭圆处处为圆的极小曲面的单位切丛.此外,我们提供了几个应用程序的子流形的中曲率向量场具有恒定的长度,一个更弱的条件比平行。

英文摘要:

In this paper, we investigate geometric conditions for isometric immersions with positive index of relative nullity to be cylinders. There is an abundance of noncylindrical $n$-dimensional minimal submanifolds with index of relative nullity $n-2$, fully described by Dajczer and Florit \cite{DF2} in terms of a certain class of elliptic surfaces. Opposed to this, we prove that nonminimal $n$-dimensional submanifolds in space forms of any codimension are locally cylinders provided that they carry a totally geodesic distribution of rank $n-2\geq2,$ which is contained in the relative nullity distribution, such that the length of the mean curvature vector field is constant along each leaf. The case of dimension $n=3$ turns out to be special. We show that there exist elliptic three-dimensional submanifolds in spheres satisfying the above properties. In fact, we provide a parametrization of three-dimensional submanifolds as unit tangent bundles of minimal surfaces in the Euclidean space whose first curvature ellipse is nowhere a circle and its second one is everywhere a circle. Moreover, we provide several applications to submanifolds whose mean curvature vector field has constant length, a much weaker condition than being parallel.

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