Minimal Generalizations under OI-Implication

The adoption of the object identity bias for weakening implication has lead to the definition of OI-implication, a generalization model for clausal spaces. In this paper, we investigate on the generalization hierarchy in the space ordered by OI-implication. The decidability of this relationship and the existence of minimal generalizations in the related search space is demonstrated. These results can be exploited for constructing refinement operators for incremental relational learning