Re: owl:TopObjectProperty in property chains?

Thanks for the references!  These are right on target.  I will study them.
In "Tractable Rules for OWL 2", top of page 6, there is the example to translate:

   NutAllergic(x) ∧ NutProduct(y) → dislikes(x, y)


   NutAllergic ⊑ ∃RNutAllergic.Self
   NutProduct ⊑ ∃RNutProduct.Self
   RNutAllergic ◦ U ◦ RNutProduct ⊑ dislikes

I'm temporarily gratified that this has the use of the universal role
in a role chain, similar to my original example (hence the name of this
thread).  But as I study the paper, I suspect it will say that this
example is not a tractable rule for OWL 2 (despite the title of the paper).

Thanks again,
- Jeff

Uli Sattler wrote:
>> >> Notice that the consequent has (x, y), not (x, z) so that z is 
>> unbound.  I think this
>> >> can done by turning ownsCastle(y, z) into a class description for y 
>> like OwnsCastle(y) with
>> >> a someValuesFrom restriction on ownsCastle
>> >>
>> >> Class: OwnsCastle  SubClassOf: ownsCastle some owl:Thing
>> >>
>> >> Then the rule becomes one which can be converted to OWL:
>> >>
>> >> hasParent(x, y) ^ OwnsCastle(y) -> hasRichParent(x, y)
>> >>
>> >
>> >> You see what I'm getting at.  In general, I'm interested in the way 
>> that
>> >> "Rewriting Rules into SROIQ Axioms" turns
>> >> rules with variables into axioms without variables.
>> >
>> > it's described in the papers mentioned earlier...but I think have a 
>> question in mind but you don't want to go through the algorithm's details?
>> I am interested in the algorithm details but fear I don't have the proper
>> context for what I was reading.  "Tight Integration of Description 
>> Logics and Disjunctive Datalog"
>> by Rosati talks about integrating DL database with a Datalog rules engine
>> but you are still expected to write the rules in Datalog.  
> aaah, so I can understand your can find a worked-out 
> example that tries to explain the differences between OWL and rules and 
> their interaction in 
> B. Motik, U. Sattler, and R. Studer. Query Answering for OWL-DL with 
> Rules. In  Proc. of the Third International Semantic Web Conference 
> (ISWC 2004), Vol. 3298 of Lecture Notes in Computer Science. 
> Springer-Verlag, 2004. 
> ...and you can find out more about translating *some* rules *faithfully* 
> into OWL axioms in 
> E Francis Gasse, Ulrike Sattler, Volker Haarslev: Rewriting Rules into 
> SROIQ Axioms. Description Logics 2008
> Markus Krötzsch, Sebastian Rudolph, Pascal Hitzler. ELP: Tractable Rules 
> for OWL 2. ISWC2008,  2008. 
> Markus Krötzsch, Sebastian Rudolph, Pascal Hitzler. Description Logic 
> Rules. ECAI2008,  2008. 
> *
> *

Received on Thursday, 28 August 2008 07:52:55 UTC