Towards Vague Query Answering in Logic Programming for Logic-based Information Retrieval

We address a novel issue for logic programming, namely the problem of evaluating ranked top-k queries. The problem occurs for instance, when we allow queries such as ``find cheap hotels close to the conference location'' in which vague predicates like cheap and close occur. Vague predicates have the effect that each tuple in the answer set has now a score in [0,1]. We show how to compute the top-k answers in case the set of facts is huge, without evaluating all the tuples.