First of all, I want to express my gratitude towards my advisors Bernd Sturmfels and Peter Bürgisser. I am very happy about our open and trustful relationship. Both of you gave me a lot of support, mathematically and personally, so the German term Doktorvater really applies to both of you. Knowing Peter Bürgisser already since the second year of my Bachelor studies in Paderborn, I received a lot of education, advise and encouragement from his side. Teaching together was always fun, both in Paderborn and Berlin. I am thankful that Bernd Sturmfels gave me the chance to pursue a PhD in algebraic geometry, although I had almost no prior knowledge in this area. Your excitement about mathematics gave me inspiration and motivation to keep on learning and exploring, and I really enjoyed writing papers with you.