PDDL+ includes the timed initial literal construct of PDDL2.2 (which provides a syntactically convenient way of expressing the class of events that can be predicted from the initial state). Although derived predicates are a powerful modelling concept, they have not so far been included in PDDL+. Further work is required to explore the relationship between derived predicates and the start-process-stop model and we do not consider this further in this paper.