On 12.11.2015 22:09, Peter F. Patel-Schneider wrote:
On 11/12/2015 09:10 AM, Markus Krötzsch wrote:
[...]
On the other hand, it is entirely possible to implement correct OWL QL (note:
*QL* not *RL*) reasoning in SPARQL without even using "rules" that need any
recursive evaluation [3]. This covers all of RDFS, and indeed some of the
patterns in these queries are quite well-known to Wikidata users too (e.g.,
using "subclassOf*" in a query). Depending on how much of OWL QL you want to
support, the SPARQL queries you get in this case are more or less simple. This
work also gives arguments as to why this style of SPARQL-based implementation
does (most likely) not exist for OWL RL [3].
Does OWL QL cover *all* of RDFS, even things like subproperties of
rdfs:subclassOf and rdfs:subPropertyOf?
No, surely not. What I meant is the RDFS-fragment of OWL DL here (which
is probably what RDFS processors are most likely to implement, too).
I think I recall you showing P-hardness of RDFS proper a while ago,
which would obviously preclude translation into single SPARQL 1.1
queries (unless NL=P).
Markus
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