Using temporal logic for modular specification of telephone services

We outline a methodology for the modular speciication of telephone services within rst-order linear-time temporal logic. Typically, the services ooered by a telephone system consist of a basic service and several optional additional services, such as automatic callback, redirection, etc. We argue informally that temporal logic provides a exible formalism for the speciication of individual services, and for the composition of diierent services. We present a style of speciication, in which the expected behavior of each additional service can be speciied independently of other services. In this style, it is straightforward to compose noninteracting services. We outline, by means of examples, how certain interactions between services that prescribe connicting behavior can manifest themselves as inconsistencies when the services are composed. We then outline how the resolution of such interactions can be described in the formalism.