KULeuven - UCLouvain working seminar, Fall 2013

Extensions of amenable groups by recurrent groupoids (after K. Juschenko, V. Nekrashevych and M. de la Salle)

Abstract: The talks will center around the article Extensions of amenable groups by recurrent groupoids by K. Juschenko, V.Nekrashevych and Mikael de la Salle, available here. We will also cover background material on amenability, Cantor dynamics, branch groups and their ramifications in holomorphic dynamics.

Framework: This activity belongs to the IAP project DYGEST.

Organisers:
Pierre-Emmanuel Caprace and Stefaan Vaes

Locations

The talks will be given alternatively at the KUL and at the UCL.
The talks at KUL take place in room B.02.18 of the Math building, located Celestijnenlaan 200B, 3001 Heverlee. Directions can be found here.
All the talks at UCL take place in room Cycl 08 of the Math building, located chemin du Cyclotron 2, 1348 Louvain-la-Neuve. Directions can be found here.

Main references

[BGS] L. Bartholdi, R. Grigorchuk, Z. Sunic, Branch groups, Handbook of algebra, Vol. 3, 989-1112, North-Holland, Amsterdam, 2003.

[JNS] K. Juschenko, V.Nekrashevych and Mikael de la Salle, Extensions of amenable groups by recurrent groupoids, arXiv.

Schedule

Friday 8th November 2013 at KUL

14:30 Pierre-Emmanuel Caprace (UCL): Introduction: amenability for homeomorphism groups of the Cantor set.

16:00 Stefaan Vaes (KUL): Discrete random walks, recurrence and capactiy.

Monday 25th November 2013 at UCL

14:30 Niels Meeschaert (KUL): A characterization of recurrence. (Lemma 2.7 and Theorem 2.8 from [JNS])

16:00 Matthias Grüninger (UCL): Proof of Theorem 3.1 from [JNS].

Friday 6th December 2013 at KUL

14:30 David Hume (UCL): Groups acting on rooted trees. (Finite-state automata, Basilica and Grigorchuk groups, Theorem 4.11 from [JNS])

16:00 Tim de Laat (KUL): Topological full groups of Cantor minimal systems. (Recovering the Juschenko-Monod Theorem)

Friday 13th December 2013 at KUL

13:45 Stefaan Vaes (KUL): A synthetic approach to the amenability criterion.

14:30 Mihai Berbec (KUL): More automata groups.

16:00 Corina Ciobotaru (UCL): Connections with holomorphic dynamics.

Abstract:	The talks will center around the article Extensions of amenable groups by recurrent groupoids by K. Juschenko, V.Nekrashevych and Mikael de la Salle, available here. We will also cover background material on amenability, Cantor dynamics, branch groups and their ramifications in holomorphic dynamics.

Framework:	This activity belongs to the IAP project DYGEST.
Organisers:	Pierre-Emmanuel Caprace and Stefaan Vaes

[BGS]	L. Bartholdi, R. Grigorchuk, Z. Sunic, Branch groups, Handbook of algebra, Vol. 3, 989-1112, North-Holland, Amsterdam, 2003.
[JNS]	K. Juschenko, V.Nekrashevych and Mikael de la Salle, Extensions of amenable groups by recurrent groupoids, arXiv.

14:30	Pierre-Emmanuel Caprace (UCL): Introduction: amenability for homeomorphism groups of the Cantor set.

16:00	Stefaan Vaes (KUL): Discrete random walks, recurrence and capactiy.

14:30	Niels Meeschaert (KUL): A characterization of recurrence. (Lemma 2.7 and Theorem 2.8 from [JNS])

16:00	Matthias Grüninger (UCL): Proof of Theorem 3.1 from [JNS].

14:30	David Hume (UCL): Groups acting on rooted trees. (Finite-state automata, Basilica and Grigorchuk groups, Theorem 4.11 from [JNS])

16:00	Tim de Laat (KUL): Topological full groups of Cantor minimal systems. (Recovering the Juschenko-Monod Theorem)

13:45	Stefaan Vaes (KUL): A synthetic approach to the amenability criterion.

14:30	Mihai Berbec (KUL): More automata groups.

16:00	Corina Ciobotaru (UCL): Connections with holomorphic dynamics.