-----Original Message----- > From: www-rdf-rules-request@w3.org [mailto:www-rdf-rules-request@w3.org] On Behalf Of Zhu Bin > Sent: Monday, December 08, 2003 4:57 PM > To: www-rdf-rules@w3.org > Subject: about last question > > > The swrl example: > hasParent(?x1, ?x2) ? hasBrother(?x2, ?x3) => hasUncle(?x1, ?x3) > can I only use OWL to assert these? > Hi Zhu Bin, You cannot use OWL to express the uncle relationship. OWL is based on description logics, and it is known that description logics bear a number of expressiveness restrictions. That is why we need a rules language. The following is another example which cannot be captured in OWL, which is adapted from [1]. According to [1], the following cannot be described in OWL because "it is impossible to describe classes whose instances are related to another anonymous individual via different property paths." if job:worksFor(?x,?y) and life:livesIn(?x,?z) and geo:locatedIn(?y,?w) and geo:locatedIn(?z,?w) then job:HomeWorker(?x); Here, job:HomeWorker can only be defined in SWRL or other rules language. regards, Minsu [1] B. Grosof, I. Horrocks et al. "Description Logic Programms" (http://www.cs.man.ac.uk/~horrocks/Publications/download/2003/p117-groso f.pdf)Received on Monday, 8 December 2003 03:35:18 GMT
This archive was generated by hypermail 2.2.0 + w3c-0.30 : Friday, 25 March 2005 11:20:50 GMT