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Combining Norms to Prove TerminationSamir Genaim, Michael Codish, John Gallagher and Vitaly Lagoon
Third International
Workshop on Verification, Model Checking and Abstract
Interpretation;
2002
Abstract:Automatic termination analysers typically measure the size of terms applying norms which are mappings from terms to the natural numbers. This paper illustrates how to enable the use of size functions defined as tuples of these simpler norm functions. This approach enables us to simplify the problem of deriving automatically a candidate norm with which to prove termination. Instead of deriving a single, complex norm function, it is sufficient to determine a collection of simpler norms, some combination of which, leads to a proof of termination. We propose that a collection of simple norms, one for each of the recursive data-types in the program, is often a suitable choice. We first demonstrate the power of combining norm functions and then the adequacy of combining norms based on regular-types.Available: bibtex entry postscript Related sites: Michael Codish The Department of Computer Science Ben-Gurion University of the Negev PoB 653, Beer-Sheva, 84105, Israel mcodish@cs.bgu.ac.il
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