Expressiveness of Real-Time Temporal Logics

A common dilemma in verification is the trade-off between the expressiveness of a specification language and the computational cost of using it.  In the realm of logics used to reason about linear time this issue manifests itself in several ways: over finite and discrete structures this is largely a question about succinctness of representation as most logics are decidable and many are equi-expressible; but over continuous and timed domains there is a clear distinction between expressive completeness and decidability.  One consequence of this distinction is the development of many different temporal logics for timed systems, each with varying expressive capabilities.  In this talk I will survey the descriptive power of some of these temporal logics and discuss the translation of classical expressiveness results into the exotic world of timed domains.