Coverage - based semi - distance between

In the present paper we use the approach of height functions to deening a semi-distance measure between Horn clauses. This appraoch is already discussed elsewhere in the framework of propositional and simple rst order languages (atoms). Hereafter we prove its applicability for Horn clauses. We use some basic results from lattice theory and introduce a family of language independent coverage-based height functions. Then we show how these results apply to Horn clauses. We also show an example of conceptual clustering of rst order atoms, where the hypotheses are Horn clauses.