Modal logic as a design notation

A notation to describe software system designs is given, together with the means to verify properties over them. Designs are considered as models of a modal logic. The procedure to derive the modal model associated to a design, the algorithm to check properties over a model, the method to define new relations and the method of model filtration are presented. The proposed logic (KPI, a poly-modal logic with inverse operators) is used as a property specification language verified through a model checking algorithm. The methods provided proved to be effective and simple to implement. A prototype tool has been developed in SML-NJ covering all functionalities described.