buondì,
domani inizia il ciclo di seminari di geometria: saranno sempre
*martedì* alle 14 in aula seminari. Notiamo il cambiamento di giorno
rispetto all'anno scorso.
Vi invio i dati per i prossimi due seminari.
a presto,
Bruno Martelli.
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MARTEDI' 7 OTTOBRE 2014
SEMINARI DI GEOMETRIA
14:00-15:00, Sala Seminari (Dip. Matematica)
On convex polyhedra as regular and polynomial images of R^n.
Carlos Ueno (Università di Pisa)
Abstract:
After giving an introduction to the origins of the problem, we
study how to obtain constructively convex polyhedra as regular images
of R^n, and advance further progress on the subject.
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MARTEDI' 14 OTTOBRE 2014
SEMINARI DI GEOMETRIA
14:00-15:00, Sala Seminari (Dip. Matematica)
Ergodicty of the mapping class group action on a component of the
character variety.
Juan Souto (CNRS - Université de Rennes)
Abstract:
Goldman proved that the variety X_g of conjugacy classes of
representations of a surface group of genus g into PSL_2R has 4g-3
connected components X_g(2-2g), ... ,X_g(2g-2) indexed by the Euler
number of the representations therein. The two extremal components
X_g(2-2g) and X_g(2g-2) correspond to Teichmueller spaces on which the
mapping class group acts discretely. On the other hand Goldman
conjectured that the action on each one of the other components is
ergodic. I will explain why this is indeed the case the component
X_g(0) consisting of representations with Eulernumber 0 and for all
g>=3. The basic technical result is a formula relating the euler
number of a representation and the infimum of the energies of
equivariant harmonic maps where the infimum is taken over all maps and
all conformal structures on the surface of genus g.