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Discrete Rigidity Phenomena in Additive Combinatorics |
| November 03, 2008 to November 07, 2008 |
| Organized By: Ben Green (University of Cambridge), Bryna Kra (Northwestern University), Emmanuel Lesigne (University of Tours), Anthony Quas (University of Victoria), Mate Wierdl (University of Memphis) |
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| Parent Programs: |
| Ergodic Theory and Additive Combinatorics |
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| Return to Workshop Description |
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Rigidity of unipotent joinings in positive characteristic.
Wednesday November 5, 2008
09:00AM - 09:45AM
Speakers:
Manfred Einsiedler
Abstract:
We will discuss joinings of horospherical subgroups (in positive
characteristic) and describe how to derive the following theorem from
their characterization. Let X be the quotient of, say for simplicity,
G=SL(n,K) by a lattice Gamma (where K is a local field). Any diagonal
G-orbit in X^2 is either dense or closed. Clearly the meniontioned
results are special cases of Ratner's celebrated theorems if K has
zero characteristic, but for K having positive characteristic, this is
joint work with Amir Mohammadi.
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