Generalizing programs via subsumption

In this paper we present a class of operators for Machine Learning based on Logic Programming which represents a characterization of the subsumption relation in the following sense: The clause C, subsumes the clause C-2 iff C-1 can be reached from C-2 by applying these operators. We give a formalization of the closeness among clauses based on these operators and an algorithm to compute it as well as a bound for a quick estimation. We extend the operator to programs and we also get a characterization of the subsumption between programs. Finally, a weak metric is presented to compute the closeness among programs based on subsumption.