|I know that the official deadline for comments has expired, but I was
only just made aware of this issue.
>From the entailment checker section in the conformance document  it seems that OWL 2 RL does not have the standard OWL 2 direct semantics, but only the RDF-based semantics. I do not understand why this is the case, as OWL 2 RL is a syntactic subset of OWL 2. One of the problems is that an OWL 2 RL entailment checker can, according to the current definition, only take RDF documents as input; not OWL ontology documents. A more serious problem is that the RDF-based semantics is generally quite hard to understand, and the relationship with the direct semantics is not obvious. It will thus be very hard to implement OWL 2 RL for anyone who has a rule reasoner that does not work on the RDF level.
I strongly suggest to reconsider the semantics of OWL 2 RL, and give it the same semantics as OWL 2 DL.
To: Jos de Bruijn <firstname.lastname@example.org>
Subject: [LC response] To Jos de Bruijn
Thank you for your comment
on the OWL 2 Web Ontology Language last call drafts.
Thank you for pointing this out. The intention is that all OWL profiles can be interpreted according to either the Direct semantics or the RDF-based semantics. Thus an OWL RL implementation using the Direct semantics would be conformant. We have revised the text in the Conformance specification to make this clear.
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