Web services semantic model system

With the development of the internet technology and software engineering, web services has been more and more important in many universal interoperability practice. In this blooming fielding, the Web Services Description Language Version 2.0 (WSDL 2.0) recommendation, an XML language for describing Web services, has provided in 26 June 2007 W3C. It is more and more important to construct a correct Web services. For improving the reliable, safe, and high quality web service, constructing development component is necessary. This paper provides a mathematical model for WSDL 2.0, and a formal model, specification, and semantics of web services based on the pre-condition logic in Hoare and He's Unifying Theories of Programming (UTP) and at same time extends it.