- From: Bijan Parsia <bparsia@cs.man.ac.uk>
- Date: Sat, 27 Jun 2009 18:46:40 -0400
- To: "Michael Schneider" <schneid@fzi.de>
- Cc: "Boris Motik" <boris.motik@comlab.ox.ac.uk>, "OWL 1.1" <public-owl-wg@w3.org>
On 27 Jun 2009, at 17:11, Michael Schneider wrote: [snip] > But from what you say above, a second issue seems to arise: It looks > to me > that OWL 2 DL now does not even allow to state /single/ property > assertions > with blank nodes in both subject and predicate position. Because, as > you > said, with > > ObjectPropertyAssertion( ex:p _:s _:o ) > > one will always also have > > ObjectPropertyAssertion( InverseObjectProperty(ex:p) _:o _:s ) > > and so there are in fact always /two/ triples Triples aren't properties. There's only one property here. One relation. Think of the model. > (though only one of them > explicitly stated) with their contained blank nodes building a > circular > structure. To have a cycle you need at least two segments. Here you have a line which you can go back and forth on. Consider _:x p _:y. _:y p _:z. You *still* don't have a cycle. You can't get to x, through z without going through _:y *twice*. If it were a cycle, you could get back to _:x directly. Cheers, Bijan.
Received on Saturday, 27 June 2009 22:47:21 UTC