Alon Levy

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A data-integration system provides a uniform interface to a multitude of data sources. Consider a data-integration system providing information about movies from data sources on the World Wide Web. There are numerous sources on the Web concerning movies, such as the Internet Movie Database (which provides comprehensive listings of movies, their casts,(More)
We consider the problems of equivalence, satissability and query-reachability for datalog programs with negation and dense-order constraints. These problems are important for optimizing datalog programs. We show that both query-reachability and satissability are decidable for programs with stratiied negation provided that negation is applied only to EDB(More)