Complex Role Inclusions with Role Chains on the Right are Expressible in SROIQ

The syntax of both SROIQ and OWL 2 allow complex role inclusion axioms where the role composition occurs on the left of the subsumption relation, but not where the role composition occurs on the right. This paper proves that, despite the lack of syntax, SROIQ, and consequently OWL 2, can already express such complex role inclusions. This is shown by proving that complex role inclusion axioms where the role composition occurs on the right of the subsumption relation can already be expressed in terms of complex role inclusions on the left. The resulting syntactic restrictions are similar to those already present in SROIQ and OWL 2. Complex Role Inclusions with Role Chains on the Right are Expressible in SROIQ