on is based on the
paper</p><p>  'Pushing the EL envelope' by Baader, Brandt, Lutz. IJCAI. Vol. 5. 2005.</p><p>The paper does not cover the whole OWL 2 EL profile and makes some
assumptions w.r.t. the allowed axioms. Given the set BC that contains</p><p>- owl:Thing
- all concept names
- all nominals { a } (with just one individual!)
- concrete domain descriptions p(f1, ..., fk) (not used here)</p><p>The allowed general concept inclusions are the following (with C1, C2 \in BC,
D \in BC \cup { owl:Nothin }):<