Francois Loeser: On the homotopy type of Berkovich spaces
Abstract: To give some motivation, we shall start by  reviewing some 
recent
work of Thuillier, Berkovich and Nicaise, showing that the topology of the
Berkovich analytification
of an algebraic variety encodes important information about varieties and
their degenerations. We shall then present recent results obtained in
collaboration with Ehud Hrushovski:
Berkovich analytifications of   algebraic varieties retract to finite
CW-complexes and are locally contractible. Our approach uses some advanced
tools from Model Theory.
We shall try to give at least some glimpses of  what these are and what 
they
are good for.