Hostname: page-component-586b7cd67f-rdxmf Total loading time: 0 Render date: 2024-11-24T17:41:17.816Z Has data issue: false hasContentIssue false

Non-divergence of unipotent flows on quotients of rank-one semisimple groups

Published online by Cambridge University Press:  28 December 2015

C. DAVIS BUENGER
Affiliation:
100 Math Tower, 231 West 18th Avenue, Columbus OH, 43210-1174, USA email [email protected], [email protected]
CHENG ZHENG
Affiliation:
100 Math Tower, 231 West 18th Avenue, Columbus OH, 43210-1174, USA email [email protected], [email protected]

Abstract

Let $G$ be a semisimple Lie group of rank one and $\unicode[STIX]{x1D6E4}$ be a torsion-free discrete subgroup of $G$ . We show that in $G/\unicode[STIX]{x1D6E4}$ , given $\unicode[STIX]{x1D716}>0$ , any trajectory of a unipotent flow remains in the set of points with injectivity radius larger than $\unicode[STIX]{x1D6FF}$ for a $1-\unicode[STIX]{x1D716}$ proportion of the time, for some $\unicode[STIX]{x1D6FF}>0$ . The result also holds for any finitely generated discrete subgroup $\unicode[STIX]{x1D6E4}$ and this generalizes Dani’s quantitative non-divergence theorem [On orbits of unipotent flows on homogeneous spaces. Ergod. Th. & Dynam. Sys.4(1) (1984), 25–34] for lattices of rank-one semisimple groups. Furthermore, for a fixed $\unicode[STIX]{x1D716}>0$ , there exists an injectivity radius $\unicode[STIX]{x1D6FF}$ such that, for any unipotent trajectory $\{u_{t}g\unicode[STIX]{x1D6E4}\}_{t\in [0,T]}$ , either it spends at least a $1-\unicode[STIX]{x1D716}$ proportion of the time in the set with injectivity radius larger than $\unicode[STIX]{x1D6FF}$ , for all large $T>0$ , or there exists a $\{u_{t}\}_{t\in \mathbb{R}}$ -normalized abelian subgroup $L$ of $G$ which intersects $g\unicode[STIX]{x1D6E4}g^{-1}$ in a small covolume lattice. We also extend these results to when $G$ is the product of rank-one semisimple groups and $\unicode[STIX]{x1D6E4}$ a discrete subgroup of $G$ whose projection onto each non-trivial factor is torsion free.

Type
Research Article
Copyright
© Cambridge University Press, 2015 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Dani, S. G.. On invariant measures, minimal sets and a lemma of Margulis. Invent. Math. 51(3) (1979), 239260.CrossRefGoogle Scholar
Dani, S. G.. On orbits of unipotent flows on homogeneous spaces. Ergod. Th. & Dynam. Sys. 4(1) (1984), 2534.Google Scholar
Dani, S. G.. On orbits of unipotent flows on homogeneous spaces, II. Ergod. Th. & Dynam. Sys. 6(2) (1986), 167182.Google Scholar
Dani, S. G. and Margulis, G. A.. Limit distributions of orbits of unipotent flows and values of quadratic forms. Adv. Sov. Math. 16 (1993), 91137.Google Scholar
Kleinbock, D. Y.. Quantitative nondivergence and its Diophantine applications. Homogeneous Flows, Moduli Spaces and Arithmetic (Clay Mathematics Proceedings, 10) . American Mathematical Society, Providence, RI, 2010, pp. 131153.Google Scholar
Kleinbock, D. Y. and Margulis, G. A.. Flows on homogeneous spaces and Diophantine approximations on manifolds. Ann. of Math. (2) 148 (1998), 339360.Google Scholar
Margulis, G. A.. On the Action of Unipotent Groups in the Space of Lattices. Halsted, New York, 1975.Google Scholar
Ratner, M.. On measure rigidity of unipotent subgroups of semisimple groups. Acta Math. 165 (1990), 229309.Google Scholar
Raghunathan, M. S.. Discrete Subgroups of Lie Groups. Springer, New York, 1972.CrossRefGoogle Scholar
Selberg, A.. On discontinuous groups in higher dimensional symmetric spaces. Contributions to Function Theory. 1960, pp. 147164.Google Scholar