Deadlock and lock freedom in the linear π-calculus

We study two refinements of the linear π-calculus that ensure deadlock freedom (the absence of stable states with pending linear communications) and lock freedom (the eventual completion of pending linear communications). The main feature of both type systems is a new form of channel polymorphism that affects their accuracy in a significant way: they are the first of their kind that can deal with recursive processes communicating in cyclic network topologies.