Wolfgang Lück is a C3-Professor of mathematics at the University of Bonn. Prior to Bonn, he worked as professor at the universities of Lexington, Mainz, and Münster. He obtained his PhD in 1984 at the University of Göttingen. His main research areas are topology, K- and L-theory, and L2-invariants, and has more than 140 research publications. He has supervised about 30 PhD-students. He is a recipient of the Max Planck Research Award, the Gottfried Wilhelm Leibniz Prize, and an ERC Advanced Grant. He is a member of the German National Academy of Sciences Leopoldina and of the North Rhine-Westphalian Academy of Sciences, Humanities and Arts, and is a Fellow of the American Mathematical Society. Tibor Macko is an associate professor of mathematics at the Comenius University and a research fellow at the Slovak Academy of Sciences, both in Bratislava. He obtained his PhD in 2004 from the University of Aberdeen and was later apostdoc at MPI in Bonn and at the universities at Münster and Bonn before returning to his native Slovakia. He is an author or a coauthor of more than a dozen papers on topology of manifolds.