Light PhD Seminar: Stallings theorem about ends of groups

Geometric group theory deals with the study of groups via a geometric approach. More precisely, to each group we associate a metric space in which the group acts in a desirable way and we seek to recover algebraic properties from geometric ones in the metric space. One of the central results in this area is the Stallings theorem about ends of group.
In the first part of this lecture we will motivate and make a general introduction to the fundamental tools used in geometric group theory.
In the second part we will define the number of ends of a graph and of a group, discuss some basic properties and give some examples. To finish, I will state the Stallings theorem about ends of groups and its consequences.