[Pellet-users] question about query language

[Bijan Parsia]

On Oct 26, 2007, at 4:34 PM, Swanson, Tim wrote:

>>
>> To expand a bit more on Kendall's already comprehensive post. I'm the
>> point person on the SPARQL/OWL Task Force and will be writing the  
>> spec
>> (soon I hope) (I was on the DAWG).
>>
>
> Bijan,
>
> I don't want to start an off-topic thread here, but I was wondering if
> you would be willing to answer a few questions about SPARQL/OWL. (If
> you'd like to move the discussion elsewhere, please do.)

I'll do a round here. If we get  more involved, I'd prefer we'd move  
to public-owl-dev with the subject tag [TF:SPARQL].

> I was wondering if SPARQL/OWL is expected to support "open-world"
> queries. That is, the ability to query for the satisfiability of a  
> given
> fact.

Hmm. Well, I don't see the latter is a synonym for the former. SPARQL/ 
OWL queries OWL kbs and does so with a fair bit of open worldness.

> I am writing a set of applications now where we often have to know the
> satisfiable extension of a class,

What do you mean by "satisfiable extension"?

> or the satisfiable objects for a given
> subject and property.
[snip]

Hmm. Well,
	foo bar ?x.

Will give you all the individuals that can be *proven* to be barred  
by foo. that is, that are barred by foo in every model. Mere  
satisfiability generally only requires at least one model. That is  
going to be a pretty unselective query as, I would bet, most of the  
time most of the individuals would be answered. So perhaps I don't  
understand what you're after? Perhaps an example with sample kb and  
answers desired?

foo bar a.
foo bar b.
a bar c.
c bar e.

Now, I can ask whether the following class is satisfiable:
	hasValue bar a

It is. In fact, "foo" satisfies it in every model. but I can  
consistently construct a model wherein b, c, and e all satisfy it,  
since I can consistently extend the above KB with the corresponding  
assertions.

Is this what you're after?

Cheers,
Bijan.