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Re: about last question

From: Zhu Bin <zhubin@cai.pku.edu.cn>
Date: Mon, 08 Dec 2003 22:11:25 +0800
To: www-rdf-rules@w3.org
Message-id: <ZTUZ08P2ZQJC0100CD@metc-dell-407.cai.pku.edu.cn>

Thank you very much.
I haven't finish reading that paper, I know some relationship between
DL and LP, and I know we can do some mappings from DL to def-Horn but not
all. But when like the swrl example:
Student(?x1) => Person(?x1)
The example said that it is logically equivalent to write instead
SubClassOf(Student Person), which one should I choose now?
That is when I want to assert a subsumption relation, when should I use
Rule language to assert? Only when we are using a ABox reasoner or other
situation?


-----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
 

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 09:13:15 GMT

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