Deep Equality Revisited
نویسندگان
چکیده
We revisit the notion of deep equality among objects in an ob ject database from a formal point of view We present three natural formalizations of deep equality one based on the in nite value trees associated with objects one based on the greatest xpoint of an oper ator on equivalence relations among objects and one based on indis tinguishability of objects using observations of atomic values reachable from the objects These three de nitions are then shown to be equiv alent The characterization in terms of greatest xpoints also yields a polynomial time algorithm for checking deep equality We also study the expressibility of deep equality in deductive database languages
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تاریخ انتشار 1995