queries in owl

I am new to semantic web and owl. I am trying to get some information
from
owl ontology.
It is clear how to get information about subclasses of other classes.
But in
owl is also possibility to use ObjectProperties and put some
restrictions on
classes.
The question is how to use them in queries (not in building new classes
in
ontology)? For example (using pizza ontology) I would like to get all
pizza's that have TomatoTopping. To do this (I think) I should use
ObjectProperties somehow (hasTopping property). Expected result would
be all
pizza's that have TomatoTopping but also TomatoCheesyTopping. I know
that I
can create some class with that kind of restriction (in pizza ontology
there
are some pizza's with that topping). But how to express proper query
to
reasoner with that kind of restriction? Is it possible to do this
using
SPARQL and Pellet? Or maybe I make a mistake thinking in that manner?

Sorry for maybe stupid question, but I just can't find strict answer


Wojtek

Received on Tuesday, 25 July 2006 20:31:11 UTC