In Datalog, missing values are represented by Skolem constants. More generally, in logic programming missing values, or existentially-quantified variables, are represented by terms built from Skolem functors. In an analogy to probabilistic relational models (PRMs), we wish to represent the joint probability distribution over missing values in a database or logic program using a Bayesian network. This paper presents an extension of logic programs that makes it possible to specify a joint probability distribution over terms built from Skolem functors in the program. Our extension is based on constraint logic programming (CLP), so we call the extended language CLP($lBN$). We show that CLP($lBN$) subsumes PRMs; this greater expressivity carries both advantages and disadvantages for CLP($lBN$). We also show that algorithms from inductive logic programming (ILP) can be used with only minor modification to learn CLP($lBN$) programs. An implementation of CLP($lBN$) is publicly available as part of YAP Prolog at http://www.cos.ufrj.br/vitor/Yap/clpbn.
|Publisher||MORGAN KAUFMANN PUB INC|
|Number of pages||8|
|Place of Publication||Acapulco, Mexico|
|Publication status||Published - 2003|