Buondì,
Segnalo un seminario di geometria per mercoledì prossimo alle 15. A presto, Bruno
----
26-Jun-2019 - 15:00 Sala Riunioni (Dip. Matematica) http://www.dm.unipi.it/webnew/it/aula/sala-riunioni-dip-matematica On type-preserving representations of the four-punctured sphere group http://www.dm.unipi.it/webnew/it/seminari/type-preserving-representations-four-punctured-sphere-group Tian Yang Texas A&M University
We give counterexamples to a conjecture of Bowditch that if a non-elementary type-preserving representation ρ : π1(Σg,n) → P SL(2; R) of a punctured surface group sends every non-peripheral simple closed curve to a hyperbolic element, then ρ must be Fuchsian. The counterexamples come from relative Euler class ±1 representations of the four-punctured sphere group. As a related result, we show that the mapping class group action on each non-extremal component of the character space of type-preserving representations of the four-punctured sphere group is ergodic, confirming a conjecture of Goldman in this case. The main tool we use is the lengths coordinates of the decorated character spaces defined by Kashaev. At the end of the talk, I will also mention a recent joint work with Sara Maloni and Frederic Palesi on representations of the three-punctured projective plane group.
Richiamo il seminario di geometria domani alle 15. (Purtroppo io, Leone ed alcuni studenti siamo ad una conferenza e non ci saremo -- Lo speaker è qui a Pisa solo questa settimana, ospite di Giulio Belletti, e non c'era altra soluzione.) A presto, Bruno
On Thu, Jun 20, 2019 at 10:34 AM Bruno Martelli martelli@dm.unipi.it wrote:
Buondì,
Segnalo un seminario di geometria per mercoledì prossimo alle 15. A presto, Bruno
26-Jun-2019 - 15:00 Sala Riunioni (Dip. Matematica) http://www.dm.unipi.it/webnew/it/aula/sala-riunioni-dip-matematica On type-preserving representations of the four-punctured sphere group http://www.dm.unipi.it/webnew/it/seminari/type-preserving-representations-four-punctured-sphere-group Tian Yang Texas A&M University
We give counterexamples to a conjecture of Bowditch that if a non-elementary type-preserving representation ρ : π1(Σg,n) → P SL(2; R) of a punctured surface group sends every non-peripheral simple closed curve to a hyperbolic element, then ρ must be Fuchsian. The counterexamples come from relative Euler class ±1 representations of the four-punctured sphere group. As a related result, we show that the mapping class group action on each non-extremal component of the character space of type-preserving representations of the four-punctured sphere group is ergodic, confirming a conjecture of Goldman in this case. The main tool we use is the lengths coordinates of the decorated character spaces defined by Kashaev. At the end of the talk, I will also mention a recent joint work with Sara Maloni and Frederic Palesi on representations of the three-punctured projective plane group.
geometria_pisa@lists.dm.unipi.it
-
Bruno Martelli