Timorin, Vladlen A.
Artamkin, Igor V.
Esterov Alexander I.
Feigin Evgeny B.
119048Moscow, Usacheva str., 6
phone/fax: +7 (495) 624-26-16
Low-dimensional topology and algebraic geometry Math Department of the Higher School of Economics, Room 413 Thursday, November 16, 12:00-13:30
Speaker: Roman Krytovsky
Title: Dehn's lemma and the loop theorem (Part 2)
I will prove Dehn's lemma, which roughly says that if you have an embedding of the boundary of a 2-disk into the boundary of a 3-manifold, then you can extend the mapping to an embedding of the whole disk into this 3-manifold. A central part of the proof will be a tower construction due to Papakyriakopoulos. --Speaker: Balaram Usov Title: The mapping class groups of surfaces (Part 2)
In this talk I will define the mapping class group of a surface. We will compute this group for the torus and prove an important theorem that this group is finitely generated by Dehn twists. In doing so I will define a complex of curves and mention some of its properties.