Towards a Unifying Theory for Web Services Composition
Recently the term orchestration has been introduced to address composition and coordination of web services. Several languages used to describe business processes using this approach have been presented, and most of them use the concepts of long-running transactions and compensations to cope with error handling. WS-BPEL, which is currently the most used orchestration language, also provides a Recovery Framework. However its complexity hinders rigorous treatment. In this paper, we address the notion of orchestration from a formal point of view with particular attention to transactions and compensations. In particular, we introduce web π ∞ , an untimed version of web π, and the related theory, as a foundational unifying framework for orchestration able to meet composition requirements and to encode the whole BPEL itself.
KeywordsBusiness Process Parallel Composition Business Process Execution Language Proof Tree Label Semantic
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