On the Equivalence of Distributed Systems With Queries and Communication
Distributed data management systems consist of peers that store, exchange and process data in order to collaboratively achieve a common goal, such as evaluate some query. The authors study the equivalence of such systems. They model a distributed system by a collection of Active XML documents, i.e., trees augmented with function calls for performing tasks such as sending, receiving and querying data. As their model is quite general, the equivalence problem turns out to be undecidable. However, they exhibit several restrictions of the model, for which equivalence can be effectively decided.