Normalizable Horn Clauses, Strongly Recognizable Relations, and Spi


We exhibit a rich class of Horn clauses, which we call H1 , whose least models, though possibly infinite, can be computed effectively. We show that the least model of an H1 clause consists of so-called strongly recognizable relations and present an exponential normalization procedure to compute it. In order to obtain a practical tool for program analysis, we identify a restriction of H1 clauses, which we call H2 , where the least models can be computed in polynomial time. This fragment still allows to express, e.g., Cartesian product and transitive closure of relations. Inside H2 , we exhibit a fragment H3 where normalization is even cubic. We demonstrate the usefulness of our approach by deriving a cubic control-flow analysis for the Spi calculus [1] as presented in [14].

DOI: 10.1007/3-540-45789-5_5

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@inproceedings{Nielson2002NormalizableHC, title={Normalizable Horn Clauses, Strongly Recognizable Relations, and Spi}, author={Flemming Nielson and Hanne Riis Nielson and Helmut Seidl}, booktitle={SAS}, year={2002} }