Reversible pi calculus

Abstract. We propose a reversible process algebra, that implements backtracking to pi calculus. Rpi, the introduced calculus, is based on RCCS, a reversible CCS that attaches memories to processes. There are two main difficult problems that arise when one wants a reversible pi calculus. These are due to substitution and scope extrusion. Their forward and backwards rules have to be symmetric and the semantics of the calculus, compositional.