In traditional formal approaches to knowledge representation, agents are assumed to believe all the logical consequences of their knowledge bases. As a result, reasoning in the first-order case becomes undecidable. Since real agents are constrained by resource limitations, it seems appropriate to look for weaker forms of reasoning with better computational properties. One way to approach the problem is by modeling belief. Reasoning can then be understood as the question whether a belief follows from believing the sentences in the knowledge base. This paper proposes...