AcknowledgmentsI wish to thank my supervisor Nicolai Viol and Prof. Dr. Wehrle for the opportunityto work on the fascinating subject of this thesis. Without their guidance, theirsupport and especially the challenging and constructive discussions, the thesis wouldnot have been completed with a satisfying result.Beside my supervisor, I want to thank my team at semantics for allowing me todedicate my time fully onto the presented topic. Without their efforts, this thesiswould not have been possible.I'm also grateful for all the help of my friends: Mirjam, Kadir, Albert, and Chrissito proofread the text and dig out all the invisible inconsistencies.Last, but not least, I must thank my wife Christine for her support and endlesspatience during the last six months.