RE: dependency analysis of OWL axioms

No, I would not necessarily translate an OWL ontology to an RDF graph for these purposes, but to another graph representation, perhaps, for graph dependency analysis. Also, just to be clear, I would say that the so-called "inferred model" of the ontology, i.e., materializing from the base model to the model extended with explicit subsumption, equivalence, etc., relations is probably the way to go.

I understand that the semantics of the OWL ontology is not preserved by a simple rendition into RDF. In OWL 1, we used to talk about "dark triples", i.e., semantically uninterpretable triples.

What I was trying to understand was why you thought that an OWL ontology could not be represented as a graph (not that it had to be represented as an RDF graph). Perhaps we are talking around each other?

Thanks,
Leo

>-----Original Message-----
>From: Pavel Klinov [mailto:pavel.klinov@uni-ulm.de]
>Sent: Saturday, November 15, 2014 4:18 PM
>To: Obrst, Leo J.
>Cc: Pavel Klinov; Leila Bayoudhi; semantic-web@w3.org
>Subject: Re: dependency analysis of OWL axioms
>
>On Sat, Nov 15, 2014 at 9:52 PM, Obrst, Leo J. <lobrst@mitre.org> wrote:
>> Sure, but I do think that is generally very useful, even if it is syntactic.
>
>First, no, it's not just syntactic; there's semantic compatibility
>between OWL and RDF, too.
>
>Second, it's useful but typically for some specific purposes, like
>exchanging OWL documents in RDF or storing OWL ontologies in RDF (e.g.
>in triple stores).
>
>However, when it comes to performing some sort of analysis on an OWL
>ontology, such as "what depends on the given axiom", then it is
>usually wrong to convert the ontology into RDF and analyse the
>resulting RDF graph. You lose the structure of the ontology as a
>logical theory and end up with a set of triples, from which it's not
>even easy to recover original axioms. Even parsing of RDF back into
>OWL isn't all that straightforward, let alone more complicate
>analyses.
>
>>
>> Or are you meaning that because first-order logic is semi-decidable it is not
>useful to represent axioms and theorems as graphs? I.e., ultimately, that a
>graph-dependency analysis of an ontology is not useful?
>
>Hm, I fail to see how the first question is even relevant to the
>discussion. Re: the second, I think one should first understand what's
>meant by "dependency" and only then suggest methods. And if by
>"graph-dependency analysis of an ontology" you mean "convert it to RDF
>and analyse", then I do think it is wrong.
>
>Pavel
>
>>
>> Thanks,
>> Leo
>>
>>>-----Original Message-----
>>>From: Pavel Klinov [mailto:pavel.klinov@uni-ulm.de]
>>>Sent: Saturday, November 15, 2014 3:17 PM
>>>To: Obrst, Leo J.
>>>Cc: Pavel Klinov; Leila Bayoudhi; semantic-web@w3.org
>>>Subject: Re: dependency analysis of OWL axioms
>>>
>>>On Sat, Nov 15, 2014 at 9:01 PM, Obrst, Leo J. <lobrst@mitre.org> wrote:
>>>> Pavel,
>>>>
>>>> How is a GCI not representable as a graph? I understand that all OWL
>>>ontologies can be represented as graphs, by definition into RDF graphs. Do
>you
>>>mean something else?
>>>
>>>In you read my first reply to you carefully, you will see that I did
>>>acknowledge it:
>>>
>>>"Of course, one can invoke the OWL2RDF mapping and take the resulting
>>>set of triples as a (kind of) graph, but I doubt it can be generally
>>>useful."
>>>
>>>But what are you going to do with that graph then?
>>>
>>>Cheers,
>>>Pavel
>>>
>>>>
>>>> Thanks,
>>>> Leo
>>>>
>>>>>-----Original Message-----
>>>>>From: Pavel Klinov [mailto:pavel.klinov@uni-ulm.de]
>>>>>Sent: Saturday, November 15, 2014 5:08 AM
>>>>>To: Obrst, Leo J.
>>>>>Cc: Pavel Klinov; Leila Bayoudhi; semantic-web@w3.org
>>>>>Subject: Re: dependency analysis of OWL axioms
>>>>>
>>>>>On Fri, Nov 14, 2014 at 10:51 PM, Obrst, Leo J. <lobrst@mitre.org> wrote:
>>>>>> Thanks, Pavel.
>>>>>>
>>>>>> My question is about your comment:
>>>>>>
>>>>>> "OWL is quite a rich language and one can write very complex axioms
>>>which
>>>>>don't look anything graph-like."
>>>>>>
>>>>>> I'd like to know your thoughts on this.
>>>>>
>>>>>For example, in OWL 2 DL one can take all (class) axioms and re-write
>>>>>all that into a single long GCI.
>>>>>
>>>>>Cheers,
>>>>>Pavel
>>>>>
>>>>>>
>>>>>> Thanks!
>>>>>> Leo
>>>>>>
>>>>>>>-----Original Message-----
>>>>>>>From: Pavel Klinov [mailto:pavel.klinov@uni-ulm.de]
>>>>>>>Sent: Friday, November 14, 2014 3:59 PM
>>>>>>>To: Obrst, Leo J.
>>>>>>>Cc: Leila Bayoudhi; semantic-web@w3.org
>>>>>>>Subject: Re: dependency analysis of OWL axioms
>>>>>>>
>>>>>>>On Fri, Nov 14, 2014 at 5:42 PM, Obrst, Leo J. <lobrst@mitre.org> wrote:
>>>>>>>> We had proposed this a number of years ago, but never had time to
>go
>>>>>down
>>>>>>>that path. More towards trying to infer "integrity constraints"
>dynamically
>>>>>(yes,
>>>>>>>OWL is Open World; integrity constraints are Closed World). Finding the
>>>>>ripple
>>>>>>>effect of deleting, adding, moving graph nodes that kind of corresponds
>to
>>>>>>>"referential integrity" (i.e., structural) in the database world. Since all
>OWL
>>>>>>>ontologies (the axioms) can be represented as graphs, it should be
>doable.
>>>>>How
>>>>>>>efficiently, I don't know.
>>>>>>>>
>>>>>>>
>>>>>>>I'd be very, very cautious with statements like "OWL axioms can be
>>>>>>>represented as graphs". In what precisely sense can they be
>>>>>>>represented as graphs? OWL is quite a rich language and one can write
>>>>>>>very complex axioms which don't look anything graph-like. Of course,
>>>>>>>one can invoke the OWL2RDF mapping and take the resulting set of
>>>>>>>triples as a (kind of) graph, but I doubt it can be generally useful.
>>>>>>>
>>>>>>>I can imagine that for some very specific tasks, like decomposition
>>>>>>>(as in [1]), a graph-based representation of OWL axioms can be
>>>>>>>helpful. But such use cases (and the corresponding representations)
>>>>>>>tend to be pretty specific rather than generic.
>>>>>>>
>>>>>>>Cheers,
>>>>>>>Pavel
>>>>>>>
>>>>>>>[1] Francisco Martín-Recuerda, Dirk Walther: Axiom Dependency
>>>>>>>Hypergraphs for Fast Atomic Decomposition of Ontologies. Description
>>>>>>>Logics 2014: 299-310
>>>>>>>
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Leo
>>>>>>>>
>>>>>>>>>-----Original Message-----
>>>>>>>>>From: Leila Bayoudhi [mailto:bayoudhileila@yahoo.fr]
>>>>>>>>>Sent: Friday, November 14, 2014 6:36 AM
>>>>>>>>>To: semantic-web@w3.org
>>>>>>>>>Subject: dependency analysis of OWL axioms
>>>>>>>>>
>>>>>>>>>Hello
>>>>>>>>>I want to know if there is a tool or an approach realizing dependency
>>>>>>>annalysis
>>>>>>>>>of OWL 2 axioms.
>>>>>>>>>Example:
>>>>>>>>>by removing a subClassOf axioms , I want to know affected ones in
>the
>>>>>>>>>ontology.
>>>>>>>>>Or, can I do it manually by recognizing different types of axioms and
>>>>>>>expecting
>>>>>>>>>relations between them.
>>>>>>>>>Thank you for answering me.
>>>>>>>>>--398296598-735493131-1415964971=3759
>>>>>>>>>Content-Type: text/html; charset=f-8
>>>>>>>>>Content-Transfer-Encoding: quoted-printable
>>>>>>>>>
>>>>>>>>><html><body><div style="color:#000; background-color:#fff; font-
>>>>>>>>>family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida
>Grande,
>>>>>sans-
>>>>>>>>>serif;font-size:16px"><div>Hello</div><div>I want to know if there is
>a
>>>>>tool
>>>>>>>or
>>>>>>>>>an approach realizing dependency annalysis of OWL 2
>>>>>>>>>axioms.</div><div>Example:&nbsp;</div><div>by removing a
>>>subClassOf
>>>>>>>>>axioms , I want to know affected ones in the ontology.</div><div>Or,
>>>can I
>>>>>>>do it
>>>>>>>>>manually by recognizing different types of axioms and expecting
>>>relations
>>>>>>>>>between them.</div><div>Thank you for answering
>>>>>>>>>me.</div></div></body></html>
>>>>>>>>>--398296598-735493131-1415964971=3759--
>>>>>>>>>
>>>>>>>>

Received on Saturday, 15 November 2014 21:31:41 UTC