Approximate pure nash equilibria in congestion, opinion formation and facility location games / submitted by Matthias Feldotto ; [Advisor: Assistant Professor Dr. Alexander Skopalik, Reviewers: Assistant Professor Dr. Alexander Skopalik, Senior Lecturer Dr. Martin Gairing, Members of the Doctoral Panel: Prof. Dr. Friedhelm Meyer auf der Heide, Assistant Professor Dr. Alexander Skopalik, Senior Lecturer Dr. Martin Gairing, Prof. Dr. Claus-Jochen Haake, Dr. Rainer Feldmann]