 Together, Inclusion and Preservation say that whenever information \(E\) is consistent with  current belief \(\cap \Bel,\) \[\cap \Bel_E = \cap \Bel \cap E.\] If \({\bf F}\) is a collection of propositions and for all \(E\in {\bf F},\) the belief sets \(\Bel,\Bel_E\) satisfy the AGM principles, we say that \(\Bel_{\bf F},\) the agent’s disposition to update her qualitative beliefs given information from \({\bf F}\), satsifies the basic AGM principles.