Credulous Nonmonotonic Inference

We present a formal characterization and semantic representation for a number of credulous inference relations based on the notion of an epistemic state. It is shown, in particular, that credulous inference can be naturally represented in terms of expectations (see [Gardenfors and Makinson, 1994]). We describe also the relationships between credulous and usual skeptical nonmonotonic inference and show how they can facilitate each other.