Modal logics for mobile processes

In process algebras, bisimulation equivalence is typically defined directly in terms of the operational rules of action; it also has an alternative characterization in terms of a simple modal logic (sometimes called Hennessy-Milner logic). This paper first defines two forms of bisimulation equivalence for the pi-calculus, a process algebra which allows dynamic reconfiguration among processes; it then explores a family of possible logics, with different modal operators. It is proven that two of these logics characterize the two bisimulation equivalences. Also, the relative expressive power of all the logics is exhibited as a lattice. The results are applicable to most value-passing process algebras