Contraction en logique propositionnelle finie

The AGM model for the revision and contraction of beliefs sets provides sets of postulates for each of the two cases. In the context of finite propositional logic, Katsuno and Mendelzon printed out some sets of postulates for the revision of belief bases which correspond to the postulates AGM revision of beliefs sets. In this paper, we present postulates for the contraction of propositional beliefs bases which correspond to the AGM postulates for the contraction of beliefs sets. We highlight the existing connections with the revision of belief sets in the sense of Katsuno and Mendelzon thanks to Levi and Harper identities and present a representation theorem for operators of contraction of beliefs sets.