Behavioral equivalence in the polymorphic pi-calculus

We investigate parametric polymorphism in message-based concurrent programm ing, focusing on behavioral equivalences in a typed process calculus analog ous to the polymorphic lambda-calculus of Girard and Reynolds. Polymorphism constrains the power of observers by preventing them from dire ctly manipulating data values whose types are abstract, leading to notions of equivalence much coarser than the standard untyped ones. We study the na ture of these constraints through simple examples of concurrent abstract da ta types and develop basic theoretical machinery for establishing bisimilar ity of polymorphic processes. We also observe some surprising interactions between polymorphism and alias ing, drawing examples from both the polymorphic pi-calculus and ML.