Résumé: Successful processing of an organization ’s business cases often requires the execution of external ( web) services that must be performed next to the organization ’s internal business processes. External services may be single activities or, more often, processes with arbitrary complexity. An organization usually handles its business cases in a similar way, i. e. , requests the same or similar external services. In order to support automatization of process execution, a composite process should be defined that provides a complete overview of overall processing at di .erent levels of detail and allows to control processing of business cases at runtime, i. e. , to invoke activities in external services where necessary and to observe processing at service providers ’sites as far as supported by the services. For properly combining services, interrelationships between them must be identified. This paper presents formal correctness criteria for composite services with respect to the definition of the involved services and introduces a method for de .ning correct composite services.

Langue: Anglais