Speaker: Pierre Lochak (Universite Paris Pierre et Marie Curie): Title: Grothendieck-Teichmueller theory from a topological viewpoint Abstract: I will explain the main features of what has come to be known as Grothendieck-Teichmueller theory, insisting on the technical similarity and differences between the different versions. I will also introduce a new approach which stresses profinite graphs and simplices sets rather than groups. Finally I will try to keep the prerequisites minimal.