Yves Moinard Circumscription and Horn theories , ECAI'90 (European Conf. on Artificial Intelligence) , Pitmman Publishing , Stockholm , 449--454 , aug , 1990 Abstract The ideas which led to circumscription, one of the best known non-monotonic reasoning methods, stem from logic programming and data bases theory. Latter, circumscription has evolved on its own side. As there are still many links between logic programming and circumscription, it is now time to make these connections precise. We focus on the relationship between circumscription and Horn theories, making an incursion into more general logic programs. We give the properties which explain why it is relatively easy to circumscribe Horn theories. This leads to new properties concerning the simplification of the circumscription axiom. Also this allows to extend these results to a wider class of theories and to give an answer to an old question about circumscription and definability, for any theory. This web site is maintained by René Quiniou using the Weave system from the Caravel project: http://www-caravel.inria.fr. Last modification: 10-07-2011 09:54:25