Service Specification Using Z Mícheál Mac an Airchinnigh, K&M Technologies Ltd. 1 Executive Summary

Z is a formal description language based on set theory and predicate logic [12]. In SCORE, we have investigated, through a number of case studies, how Z may be used to support service creation. Z may be used in the specification stage of service creation as it provides a succinct and unambiguous way of specifying services. Experience has shown that formal notations such as Z may also be used to aid the requirements gathering stage of the service creation process; by building partial formal models based on requirements, these requirements can be clarified and further elaborated before a more complete specification is produced. 1.1 Conceptual Model Guidelines on the use of Z for telecoms service specification are described in this report. We have taken the view that a service is provided by a system. A standard approach to system specification was taken, whereby we focus on some clearly defined notions—entities—and build appropriate relations between them. We refer to the entities and the relationships between them as a conceptua