Date: 2012-07-12 10:56:35
From: nicola.vitucci@gmail.com
Hi all,
I have another question for you :-)
Considering that OWLIM supports the OWL2 QL and RL profiles, what kinds
of TBox queries can be performed? Are queries with anonymous classes
like "find the subclasses/superclasses/equivalent classes of (R some C)"
possible (with R being a property and C a concept)? Also, are there any
limitations or additions to the "standard" profiles?
Thank you for the very good work with OWLIM, I'm appreciating it more
and more!
Nicola

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Date: 2012-07-12 13:52:59
From: barry.bishop@ontotext.com
Hi Nicola,
Thanks for your question. I am very happy that you are still interested! 
Firstly, a little information about the supported rule-sets (and 
limitations) is here:
http://owlim.ontotext.com/display/OWLIMv51/OWLIM-SE+Reasoner#OWLIM-SEReasoner-PredefinedRuleSets
OWL2-QL is not really designed for rule-based reasoning engines, but 
OWL2-RL fits very well on OWLIM. We miss only datatype reasoning.
You can ask all sorts of queries, however, they must be in SPARQL form, 
so as long as you can write your expressions in RDF/Turtle syntax then 
you can probably ask it.
In the RDF serialisation of OWL, most things become restrictions, so 
your query will probably need to involve looking for restrictions on 
properties with some cardinality constraint. Sadly, I'm not an OWL 
expert, but maybe someone else could help with this kind of query?
Good luck,
barry
Barry Bishop
OWLIM Product Manager
Ontotext AD
Tel: +43 650 2000 237
email: barry.bishop at ontotext.com
skype: bazbishop
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ate: 2012-07-12 13:13:32
From: damyan@sirma.bg
Hi Nicola,
yes, you could query for such - just express these as SPARQL queries
for instance,  a query against wordnet to get all the subclasses of a 
Restriction (wordn-sc:word some  wordn-sc:Word) may look like:
PREFIX wordn-sc: <http://www.w3.org/2006/03/wn/wn20/schema/>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
select * where {
?sub rdfs:subClassOf ?c .
?c a owl:Restriction;
owl:onProperty wordn-sc:word;
owl:someValuesFrom wordn-sc:Word .
}
About the supported inference and its limitations, best is to read 
"supported semantics" from the OWLIM Primer document 
<http://owlim.ontotext.com/display/OWLIMv50/Primer+Introduction+to+OWLIM#PrimerIntroductiontoOWLIM-SupportedSemantics> 
HTH,
Damyan Ognyanov
Ontotext AD.
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answered 03 Apr '13, 09:58

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Date: 2012-07-12 13:27:54
From: barry.norton@ontotext.com
+1
But how does such a query work with forward-chaining? (Since the class 
is unknown, therefore hasn't been subjected to the inference rules before)
My first idea was that maybe the class if asserted, reasoning enacted, 
the query answered, then the assertion rolled back... but that's not how 
Sesame transactions work.
I fear your answer might start "that's a totally stupid idea, B2"...
B2
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Date: 2012-07-17 14:25:05
From: nicola.vitucci@gmail.com
Thanks Damyan and Barry,
I am still experimenting but I could get some results within small
example TBoxes. Sometime it is necessary to use an owl:equivalentClass
within a restriction (for example when you have an intersection as a
filler), but things look like working. In any case I have two more
questions:
1) Why do new anonymous nodes appear after every query? I keep on
getting new "_:nodeX" (with X a number) every time I run the same query.
2) Maybe I haven't understood it very well but, using the owl2-rl
profile, shouldn't I be denied to use full existential restrictions on
the right side of a subsumption axiom? So why does this work?
Thanks once again, I will keep you up to date.
Nicola
Il 12/07/2012 14:52, Barry Bishop ha scritto:
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