Progol

PROGOL is a system for machine learning, which was published in 1995 by Stephen Muggleton. It belongs to the paradigm of inductive logic programming and learning definitions of concepts in predicate logic from a set of examples and background knowledge. The examples and the elements of the background knowledge can be any definite Horn clauses.

PROGOL combines the bottom-up technique of inverse entailment with a top-down search through the set of clauses. There designed to be a first example of the most specific clause that explains together with the background knowledge the example, in a limited fashion by Declarations language. Then a clause determines which subsumes the most specific clause and a compression metric maximized. This is added to the theory.

In contrast to previous methods, such as FOIL guaranteed PROGOL that the clause found in terms of the metric is optimal because it uses a variant of the A * algorithm.