  Communicating transactions is a form of distributed, non-isolated
transactions which provides a simple construct for building concurrent systems.
In this paper we develop a logical framework to express properties of the
observable behaviour of such systems. This comprises three nominal modal logics
which share standard communication modalities but have distinct past and future
modalities involving transactional commits. All three logics have the same
distinguishing power over systems because their associated weak bisimulations
coincide with contextual equivalence. Furthermore, they are equally expressive
because there are semantics-preserving translations between their formulae.
Using the logics we can clearly exhibit subtle example inequivalences. This
work presents the first property logics for non-isolated transactions.
