Abstract
This paper presents an extension of a framework for synthesizing a composition of services, named Roman Model, such that it is able to model the best service composition synthesis problem. In such extension, which we call the Weighted Roman Model, the services are modeled as Weighted Transition Systems so that one can capture the cost of operations executed by a service. Within this setting, we can make a comparison among all possible compositions of the available services by considering the total cost of operation execution performed by each possible composition of services for each interaction between the service and the client. Besides defining the notion of best composition, we also propose an algorithm for synthesizing the best composition and show that it is sound and complete. Finally, we propose an extension of WSDL to capture the Weighted Roman Model.