W3C home > Mailing lists > Public > www-rdf-rules@w3.org > December 2003

RE: about last question

From: Minsu Jang <minsu@etri.re.kr>
Date: Mon, 8 Dec 2003 17:35:05 +0900
To: "'Zhu Bin'" <zhubin@cai.pku.edu.cn>, <www-rdf-rules@w3.org>
Message-ID: <000001c3bd66$3130a010$8c4bfe81@ZEBEHN>

-----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)

Here, job:HomeWorker can only be defined in SWRL or other rules


[1] B. Grosof, I. Horrocks et al. "Description Logic Programms"
Received on Monday, 8 December 2003 03:35:18 UTC

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