Prof. S. Barry Cooper was a Professor of Pure Mathematics at the University of Leeds. He was the founding President of the Computability in Europe Association, and a prolific author and editor in the domain of computability. He championed Alan Turing”s achievements in logic and computer science, and in particular he motivated and organized cross-disciplinary collaborations, among them the events, publications and broadcasts of the Alan Turing Year in 2012. Dr. Mariya I. Soskova is an associate professor in the Dept. of Mathematical Logic and Applications in Sofia University. She was recently a visiting scholar at the University of California, and a visiting seminar professor at the Dept. of Mathematics at the University of Wisconsin, Madison.