The Hasso Plattner Institute hosts a preparation seminar for the participants of the 2nd round of the "34. Bundeswettbewerb Informatik" (National Olympiad in Informatics). As part of the seminar, Prof. Dr. Tobias Friedrich gives on 22.01.2016 a talk with the title "Der Vier-Farben-Satz (für sechs Farben)". A copy of the slides by Dr. Thomas Bläsius is available here.