Possibilistic Well-Founded Semantics

Recently, a good set of logic programming semantics has been defined for capturing possibilistic logic program. Practically all of them follow a credulous reasoning approach. This means that given a possibilistic logic program one can infer a set of possibilistic models. However, sometimes it is desirable to associate just one possibilistic model to a given possibilistic logic program. One of the main implications of having just one model associated to a possibilistic logic program is that one can perform queries directly to a possibilistic program and answering these queries in accordance with this model. In this paper, we introduce an extension of the Well-Founded Semantics, which represents a sceptical reasoning approach, in order to capture possibilistic logic programs. We will show that our new semantics can be considered as an approximation of the possibilistic semantics based on the answer set semantics and the pstable semantic. A relevant feature of the introduced semantics is that it is polynomial time computable.