Compositional Semantics for Heterogeneous Systems

The semantics of a programming language provide a precise mathematical description of its
behaviour. The semantics of systems are often defined compositionally by specifying the
semantics of smaller subsystems, and then describing how these subsystems interact with one
another. Most approaches to date rely on a level of homogeneity between these subsystems for
instance, they may be required to be defined in the same programming language. In
principle, however, a suitably rich, semantic language could facilitate the compositions of
behaviours which were defined in radically different frameworks by describing the interface
between these subsystems.
In the proposed research, we will investigate the potential role of semantics as an interface
between components in heterogeneous systems. We will use these interfaces to model larger
systems from component subsystems and to investigate appropropriate notions of observable
equivalence in these models, with possible applications to system security.