High Quality Content by WIKIPEDIA articles! Knowledge compilation is a family of approaches for addressing the intractability of a number of artificial intelligence problems. A propositional model is compiled in an off-line phase in order to support some queries in polytime. Many ways of compiling a propositional models exist . Among others: NNF, DNNF, d-DNNF, BDD, MDD, DNF and CNF. Different compiled representations have different properties.