Save Big on Coursera Plus. 7,000+ courses at $160 off. Limited Time Only! Grab it Explore a 51-minute lecture on the extensions of 1-cocycles of the mapping class group to the Ptolemy groupoid, presented by Y. Kuno from Tsuda University. Delve into the intricate connections between algebra, topology, and the Grothendieck-Teichmüller group as part of the NCCR SwissMAP series. Gain insights into advanced mathematical concepts and their applications in this in-depth talk.