Simulating expansions without expansions

Abstract : We add extensional equalities for the functional and product types to the typed l-calculus with not only products and terminal object, but also sums and bounded recursion (a version of recursion that does not allow recursive calls of infinite length). We provide a confluent and strongly normalizing (thus desidable) rewriting system for the calculus, that stays confluent when allowing unbounded recursion. For that, we turn the extensional equalities into expansion rules and not into contractions as is done traditionally. We first prove the calculus to be weakly confluent, which is a more complex and interesting task than for the usual l-calculus. Then we provide an effective mechanism to simulate expansions without expansion rules, so that the strong normalization of the calculus can be derived from that of the underlying, traditional, non extensional system. These results give us the confluence of the full calculus, but we also show how to deduce confluence directly form our simulation technique, without the weak confluence property.
Type de document :
RR-1911, INRIA. 1993
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Soumis le : mercredi 24 mai 2006 - 16:15:18
Dernière modification le : vendredi 12 octobre 2018 - 15:22:01
Document(s) archivé(s) le : mardi 12 avril 2011 - 19:10:09



  • HAL Id : inria-00074762, version 1



R. Di Cosmo, D. Kesner. Simulating expansions without expansions. RR-1911, INRIA. 1993. 〈inria-00074762〉



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