Workshop on Invariant Random Subgroups

organisation de l'atelier "IRS à Sète" pour l'ANR AGIRA

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unimodularity [2018/04/25 17:37]
jraimbau created
unimodularity [2018/04/30 18:36] (current)
ibiringer
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 === Presentation === === Presentation ===
  
-Forgetting the group structure via Schreier ​graphs, invariant random subgroups in discrete ​groups can be regarded as random ​graphs satisfying an invariance property called //​unimodularity//​. In the continuous settingone can translate IRSs in Lie groups into random Riemannian manifolds with an ad hoc invariance propertywhich makes sense beyond ​the locally symmetric ​setting+The Schreier ​graph of an IRS of a discrete ​group is a random ​pointed graph. ​ Conjugation ​invariance ​of the IRS corresponds to a property called //​unimodularity// ​in the Schreier graph which essentially captures the random base points are uniformly distributed through the graphs. 
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 +Similarly, if G is a Lie group, X is an associated symmetric space and H is an IRS of G, the quotient H \ X is a random ​pointed ​Riemannian ​manifold that satisfies a similar unimodularity property. 
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 +In two lectures, we will introduce unimodular random ​manifolds ​(URMs) and explain some of their basic properties, including the relationship ​with IRSs, the "​No-Core Theorem",​ and how to regard them as transverse measures on a universal foliated space. (This last point is a very natural version of '​unimodularity means that base points are uniformly distributed'​ that is unavailable in the graph theory setting.) ​ Time permitting, we'll mention some work with Jean on the space ends of unimodular random manifolds, and/or some work with Abert-Bergeron-Gelander on normalized Betti numbers of locally symmetric ​spaces.
  
 === References === === References ===
  
   * Ian Biringer, Omer Tamuz, //​Unimodularity of Invariant Random Subgroups//,​ Trans. AMS 2016, [[https://​arxiv.org/​abs/​1402.1042|Arxiv version]]. ​   * Ian Biringer, Omer Tamuz, //​Unimodularity of Invariant Random Subgroups//,​ Trans. AMS 2016, [[https://​arxiv.org/​abs/​1402.1042|Arxiv version]]. ​
 +  * Ian Biringer, Jean Raimbault, //Ends of unimodular random manifolds//,​ PAMS 2017, [[https://​arxiv.org/​abs/​1411.0561|Arxiv version]].
   * Miklós Abért, Ian Biringer, //​Unimodular measures on the space of all Riemannian manifolds //, [[https://​arxiv.org/​abs/​1606.03360|Arxiv preprint]]. ​   * Miklós Abért, Ian Biringer, //​Unimodular measures on the space of all Riemannian manifolds //, [[https://​arxiv.org/​abs/​1606.03360|Arxiv preprint]]. ​
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unimodularity.txt · Last modified: 2018/04/30 18:36 by ibiringer