Joint Colloquium: Zvengrowski -- Application of Homotopy Theory to Graph Colourings

In 195 M.Kneser formulated a conjecture about the number of colours needed
to colour certain graphs, which was proved in 1978 by L.Lovasz, using
techniques of algebraic topology. In this talk we shall give the simplest
version of the proof, which actually proves the more general Dol’nikov 
Theorem, and is due to J.Greene in 2002. The techniques used are fairly
elementary, so all parts of the proof will be explained and should be
accessible to students as well as faculty. If time permits some further
research of the speaker related to these questions will be discussed.