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arXiv 0705.1853math.DGmath.DS
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2-非正曲率下的框架流动力学和双曲秩刚性

2-Frame flow dynamics and hyperbolic rank rigidity in nonpositive curvature

David Constantine

摘要:

本文给出了秩为1的非正曲空间的双曲秩刚性结果。设$M$是一个紧致的秩为1的截面曲率为非正的流形,并假定沿着$M$中的每一条测地线都有一个平行向量场使曲率$-a^2$与测地线方向一致.我们证明了$M$有常曲率等于$-a^2$,如果$M$是奇数维,或如果$M$是偶数维,并有截面曲率捏如下:$-Λ^2 < K < -λ^2$其中$λ/Λ> >.93$。当$-a^2$是上曲率界这给出了一个较短的证明双曲秩刚性定理的Hamenstädt,受捏条件在偶数维;在所有其他情况下,这是一个新的结果。我们还提出了一个刚性的结果,只使用最大李雅普诺夫指数的假设,直接类比康奈尔所做的工作。通过假设严格的负曲率,主要定理的证明被大大简化;事实上,在除了7维和8维之外的所有维中,它是$(dim(M)-1)$标架流遍历性的直接结果。在这些特殊的尺寸,诉诸动力学的2-框架流必须作出和计划的证明,可以推广到处理秩1,非正弯曲的空间。

英文摘要:

This paper presents hyperbolic rank rigidity results for rank 1, nonpositively curved spaces. Let $M$ be a compact, rank 1 manifold with nonpositive sectional curvature and suppose that along every geodesic in $M$ there is a parallel vector field making curvature $-a^2$ with the geodesic direction. We prove that $M$ has constant curvature equal to $-a^2$ if $M$ is odd dimensional, or if $M$ is even dimensional and has sectional curvature pinched as follows: $-Λ^2 < K < -λ^2$ where $λ/Λ> >.93$. When $-a^2$ is the upper curvature bound this gives a shorter proof of the hyperbolic rank rigidity theorem of Hamenstädt, subject to the pinching condition in even dimension; in all other cases it is a new result. We also present a rigidity result using only an assumption on maximal Lyapunov exponents in direct analogy with work done by Connell. The proof of the main theorem is simplified considerably by assuming strict negative curvature; in fact, in all dimensions but 7 and 8 it is then an immediate consequence of ergodicity of the $(dim(M)-1)$-frame flow. In these exceptional dimensions, recourse to the dynamics of the 2-frame flow must be made and the scheme of proof developed there can be generalized to deal with rank 1, nonpositively curved spaces.

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。

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