Let S be an oriented punctured surface with negative Euler characteristic. The Ptolemy groupoid is constructed by considering the action of mapping class group MCG(S) on the set of all labeled ideal triangulations of S. The quantization of Teichmüller space T(S) induces a family of projective representations of the Ptolemy groupoid which help to construct central extensions of MCG(S). These central extensions are in the same cohomology class. By giving the presentation of a special one of them, we are able to show that this cohomology class is 12 times one fourth of Meyer signature class plus Euler classes associated to punctures.
Donnerstag, den 16. Juli 2015 um 13:15 Uhr, in INF288, HS6 Donnerstag, den 16. Juli 2015 at 13:15, in INF288, HS6
Der Vortrag folgt der Einladung von The lecture takes place at invitation by Anna Wienhard