Optimization with set relationsDissertationzur Erlangung des akademischen Gradesdoctor rerum naturalium (Dr. rer. nat.)vorgelegt derMathematisch-Naturwissenschaftlich-Technischen Fakult¨atder Martin-Luther-Universit¨at Halle-Wittenbergvon Herrn Andreas L¨ohnegeboren am 15. Oktober 1972 in QuerfurtGutachterin/Gutachter:1. Prof. Dr. Christiane Tammer, MLU Halle–Wittenberg2. Prof. Dr. Johannes Jahn, Universit¨at Erlangen–Nurn¨ bergeingereicht am: 18.01.2005Tag der Verteidigung: 27.05.2005urn:nbn:de:gbv:3-000008490[http://nbn-resolving.de/urn/resolver.pl?urn=nbn%3Ade%3Agbv%3A3-000008490]AcknowledgmentsFirst of all I would like to thank Prof. Dr. Christiane Tammer and Dr. Andreas Hamel forbeing great supervisors.I’m greatly indebted to Prof. Dr. C. Z˘alinescu from the university ”Al. I. Cuza” Iasi(Romania) for the many helpful suggestions, which influenced this work very positively.Moreover, I would like to thank all my colleagues (and former colleagues) from the Instituteof Optimization and Stochastics for the many inspiring discussions and for the good workingatmosphere at the institute.Igratefullyacknowledgethe”LandSachsen–Anhalt”andtheMartin–Luther–UniversityHalle–Wittenberg for the financial support by a scolarship over almost three years.