Mobile Processes and Termination

This paper surveys some recent works on the study of termination in a concurrent setting. Processes are $pi$-calculus processes, on which type systems are imposed that ensure termination of the process computations. Two approaches are exposed. The first one draws on the method of logical relations, which has been extensively used in the analysis of sequential languages. The second approach exploits notions from term rewriting

How can Nature help us compute

Abstract. Ever since Alan Turing gave us a machine model of algorithmic computation, there have been questions about how widely it is applicable (some asked by Turing himself). Although the computer on our desk can be viewed in isolation as a Universal Turing Machine, there are many examples in nature of what looks like computation, but for which there is no well-understood model. In many areas, we have to come to terms with emergence not being clearly algorithmic. The positive side of this is the growth of new computational paradigms based on metaphors for natural phenomena, and the devising of very informative computer simulations got from copying nature. This talk is concerned with general questions such as: • Can natural computation, in its various forms, provide us with genuinely new ways of computing? • To what extent can natural processes be captured computationally? • Is there a universal model underlying these new paradigms