Verification criteria for a compositional model for reactive systems

System composition/decomposition has to be analyzed in terms of temporal constraints associated with the components' external interface. The analysis is focused on the propagation of temporal constraints along the structural hierarchy, thus showing that in many cases missing temporal constraints can be evaluated on the basis of the temporal constraints known. A set of criteria for the verification of the temporal constraints in a compositional model is presented. A specific graphical notation is proposed. The application of the criteria to a real problem is illustrated by using TROL, an object oriented real time language.