THE CENTRE FOR ADVANCED STUDIES IN MATHEMATICS
BUCHAREST - ROMANIA

Groups almost acting on trees: algebraic and geometric aspects

Lecture series by Prof. Vlad Sergiescu (University of Grenoble).

The lectures are given at the "Simion Stoilow" Institute of Mathematics in Bucharest, Hall 414, each Friday at 11 o'clock.

1-st Lecture (9 February 2001):

Abstract: We shall introduce the main groups almost acting on trees -Thompson groups and Neretin groups - and we shall describe their place in the theory of infinite discrete groups. We shall explain the evolution of the subject untill 1990 and we shall insist on the algebraic and combinatorial aspects of the theory.

2-nd Lecture (16 February 2001):

Abstract: We shall describe the topologigal and geometric aspects of Thompson groups, mainly the link with the infinite braid group.
 

3-rd Lecture (23 February 2001):

Abstract: In the first part of the lecture,we shall complete the relation between Thomson group and braid group. The main tools of the previous lectures will be shortly presented. Then we shall try to place these results into the realm of infinite dimensional geometry related to the string theory: the group Diff(S¹) and the universal Teichmuller theory.

The Second Part of the Lecture Series will begin on May 4, 2001 at 11 o'clock at the "Simion Stoilow" Institute in Bucharest (hall 414).

4-th Lecture (4 May 2001):

Abstract: Teichmuller spaces; braids and Thompson group.

5-th Lecture (11 May 2001):

6-th Lecture (18 May 2001):