Abstract: There are several formalizations of Web services: WSMO(Web Service Modeling Ontology) and OWI-S(Web Ontology Language for Services). To analyze the logical properties of WSML,we represented WSML in a predicate dynamic logic,where the predicate dynamic logic is different from the traditional PDL which is designed to represent dynamic properties of programs which change the assignments of variables, and the predicate dynamic logic for Web services is designed to represent dynamic properties of services which change the relations. We gave the syntax and semantics of the PDI_ for Web services,and an example to show how to represent the static and dynamic properties of Web services.

Key words: Predicate dynamic logic, Web service modeling ontology, Web service, Program, Assignment