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Re: Publications about OWL (1 or 2) Full

From: David Price <davidprice.net@googlemail.com>
Date: Fri, 20 May 2011 15:11:55 +0100
Message-ID: <BANLkTik6ayaMgDfTN6M7dFZywzzh21oCeA@mail.gmail.com>
To: semantic-web@w3.org
Not sure what you tried in Composer, but you can do this as follows: click
on class Eagle, then under Other Properties, for rdf:type select Add empty
row and drag Species in as another rdf:type in addition to owl:Class. I can
also confirm that using Pellet from Composer results in the behavior
mentioned in the Tweety is an Eagle and Hawk example.

Cheers,
David


On Thu, May 19, 2011 at 8:40 PM, Michael F Uschold <uschold@gmail.com>wrote:

> I just tried the simple Eagle example in Topbraid Composer.  The tool
> prevents me from entering Eagle both as a class and as an instance of
> Species, but I can do it manually in a text file, upload it and the SPARQL
> works as intended.
>
> However, is it pure SPARQL, no OWL inferencing. So this happens
> independently of any OWL 2 DL entailment regime.
>
> I'll have to go poke arodn a bit more to see what if anything the OWL 2 DL
> entailment regime buys me in this context.
>
> Thanks again,
> Michael
>
> On Thu, May 19, 2011 at 12:25 PM, Michael F Uschold <uschold@gmail.com>wrote:
>
>> ON the Eagle Example:
>>
>>> :Species a owl:Class .
>>> :Eagle a :Species, a owl:Class ;
>>> rdfs:subClassOf :Animal .
>>> :billy a :Eagle .
>>>
>>> This is valid OWL 2 DL.
>>>
>>> Then, with a SPARQL 1.1 query with OWL 2 DL entailment regime, I can get
>>> the pairs <species,individualmemberofthespecies>:
>>>
>>> SELECT ?species, ?member WHERE {
>>> ?species a :Species .
>>> ?member a ?species .
>>> }
>>>
>>
>> > Yes, this is allowed.
>>
>> So if this returns ?species as Eagle and ?member as Billy, then SPARQL
>> must not know it is only a pun. It thinks the two are the same.  Maybe it
>> is just a syntactic link with little or no semantic import.Intriguing.
>> I'll have to try this out.
>>
>> This is a bit better than I thought. Thanks for the clarification.
>>
>>
>> On Thu, May 19, 2011 at 12:01 PM, Markus Krötzsch <
>> markus.kroetzsch@comlab.ox.ac.uk> wrote:
>>
>>> On 19/05/11 18:58, Antoine Zimmermann wrote:
>>>
>>>> First, thanks to you Michael and Markus for your replies.
>>>>
>>>> Now, Michael,
>>>>
>>>>  <snip>
>>>
>>>
>>>>>>>
>>>>>> Fortunately, OWL 2 now allows a useful form of simple meta-modelling
>>>>>> now,
>>>>>> so that you can indeed have meta classes and use classes as subjects
>>>>>> and
>>>>>> objects of properties.
>>>>>>
>>>>>
>>>>> The logical inferences that OWL 2 DL tools draw from this are limited,
>>>>> but
>>>>>
>>>>>> may still be more than what any particular OWL 2 Full reasoner would
>>>>>> give
>>>>>> you (depends on the OWL 2 Full reasoner you have -- I am not aware of
>>>>>> much
>>>>>> implementation work there beyond OWL 2 RL).
>>>>>>
>>>>>>
>>>>> Hmm, I know there is some limited punning, but these are two different
>>>>> things, not one thing appearing in two different places. The inference
>>>>> is
>>>>> very limited.
>>>>>
>>>>
>>>> What Markus says here I guess is that, in spite of the limitations of
>>>> the punning mechanism, a full-fledged OWL 2 DL reasoners will likely
>>>> infer more things than *currently existing* incomplete OWL Full
>>>> reasoners.
>>>>
>>>
>>> Right. We know that there cannot be a tool that computes all consequences
>>> of OWL with "proper" meta modelling, and we also know that some forms of
>>> meta modelling can even lead to intricate inconsistencies that make the
>>> whole ontology language paradoxical (PF Patel-Schneider's paper "Building
>>> the Semantic Web Tower from RDF Straw" alludes to this issue). So it seems
>>> that a tool that obtains all consequences of plain OWL constructs, and that
>>> can still handle some meta modelling is not such a bad choice, even if it is
>>> called "OWL DL reasoner" ;-)
>>>
>>>
>>>
>>>>
>>>>> I don't think there is a way to nicely handle the species example where
>>>>> Species is a class with instance Eagle with instances being individual
>>>>> eagles.
>>>>>
>>>>
>>>> No problem:
>>>>
>>>> :Species a owl:Class .
>>>> :Eagle a :Species, a owl:Class ;
>>>> rdfs:subClassOf :Animal .
>>>> :billy a :Eagle .
>>>>
>>>> This is valid OWL 2 DL.
>>>>
>>>> Then, with a SPARQL 1.1 query with OWL 2 DL entailment regime, I can get
>>>> the pairs <species,individualmemberofthespecies>:
>>>>
>>>> SELECT ?species, ?member WHERE {
>>>> ?species a :Species .
>>>> ?member a ?species .
>>>> }
>>>>
>>>
>>> Yes, this is allowed.
>>>
>>>
>>>
>>>>
>>>>> I also do not think there is a robust solution to the classes as values
>>>>> problem.
>>>>>
>>>>
>>>> What do you mean by "classes as values problem"?
>>>>
>>>>
>>>>  An insightful discussion of meta modelling semantics -- the one of
>>>>>> OWL 2 DL
>>>>>> (punning) and a stronger one -- is found in the paper:
>>>>>>
>>>>>> Boris Motik. On the Properties of Metamodeling in OWL. Journal of
>>>>>> Logic and
>>>>>> Computation, 17(4):617–637, 2007.
>>>>>>
>>>>>>
>>>>>>  Thanks, I just had a look. It is intersting, and geared more for the
>>>>> theorist than the practitioner. Do you know of a more practice-focused
>>>>> paper that gives examples of what you can and cannot do with OWL2
>>>>> metamodelling, compared to OWL-Full?
>>>>>
>>>>
>>> Indeed, this paper is more on the logical side of the discussion, though
>>> I still found it quite accessible. Especially, it has some examples of
>>> consequences that one looses under the weak meta modelling of OWL 2.
>>>
>>> I am not aware of a treatment of this issue that is using OWL or RDF
>>> terminology. This may not make it easier to understand, since the issues of
>>> metamodelling are often complicated by nature -- the straw tower paper
>>> mentioned above uses the RDF data model but still requires some thought to
>>> understand the key issues raised there.
>>>
>>>
>>>
>>>>>
>>>>>  A big advantage of OWL 2 DL in this respect is that it makes it legal
>>>>>> to
>>>>>> state such meta-knowledge without violating any constraints of the
>>>>>> language.
>>>>>> The OWL Full semantics may still formally lead to more consequences,
>>>>>> but in
>>>>>> practice what matters is how many of the total consequence any tool
>>>>>> will
>>>>>> actually give. So the DL approach could be a good compromise
>>>>>> (especially to
>>>>>> "make meaning clear" beyond purely logical/formal aspects).
>>>>>>
>>>>>>
>>>>> I'm not sure what you mean by "make meaning clear" as a good DL
>>>>> compromise.
>>>>> The example from that paper is the need to represent Eagle as an
>>>>> instance
>>>>> of Species so you can e.g. say it is on the engangered list. DL forces
>>>>> you
>>>>> to represent Eagle as an as an individual that can not ever have any
>>>>> instances. But this is patently untrue -- to that extent, it
>>>>> obfusticates
>>>>> meaning. If OWL2 metamodellign lets me do this, I'll be surprised and
>>>>> delighted.
>>>>>
>>>>
>>>> Punning means that you can use the URI of an individual in place of the
>>>> URI of a class. Therefore, :Eagle, as a class, can have instances (like
>>>> :billy above) and as an individual it can belong to a class (like
>>>> :Species). However, :Eagle-the-individual is different from
>>>> :Eagle-the-class, although they share the same identifier.
>>>>
>>>
>>> Exactly. This is of course a cheap form of meta modelling, but it seems
>>> that it goes a surprisingly long way in practice. Many use cases are really
>>> about modelling several "layers" of the domain of interest, but have only
>>> little interaction between these layers. Here is an example where one would
>>> see the limitation:
>>>
>>> Assume you have Eagle and Hawk as classes, and you have an individual
>>> Tweety who is said to have the species Eagle, and to have the species Hawk
>>> (as individuals). Assume further that there is a cardinality restriction
>>> that requires "has species" to be functional. Then implicitly we derive that
>>> Eagle and Hawk are the same individuals. With punning, nothing else happens.
>>> With "true" meta modelling, the classes Eagle and Hawk would also be
>>> inferred to be the same, with all the consequences that this could have..
>>>
>>> I am not sure if this is a practically relevant limitation.
>>>
>>> Cheers,
>>>
>>> Markus
>>>
>>>
>>>
>>>
>>>>>> I think the more important case where ontologies go beyond OWL DL is
>>>>>> due to
>>>>>> the structural constraints related to transitivity and property
>>>>>> chains (e.g.
>>>>>> it is easy to get forbidden cycles in property chain dependencies).
>>>>>> But the
>>>>>> interesting difference to the earlier meta-modelling limitations of
>>>>>> OWL 1 DL
>>>>>> is that in these cases, the semantics of OWL DL is in principle still
>>>>>> meaningful and well-defined in its common first-order logic
>>>>>> framework. It is
>>>>>> simply known that computing consequences of this semantics becomes
>>>>>> undecidable, and thus the decidability-loving DL tools reject the
>>>>>> inputs
>>>>>> right away.
>>>>>>
>>>>>> But again anybody who would venture to implement OWL Full reasoning
>>>>>> could
>>>>>> also look into "OWL DL reasoning for ontologies violating the
>>>>>> structural
>>>>>> restrictions." This task might be easier to solve in practice since
>>>>>> one
>>>>>> could probably reuse existing algorithms and tools to solve part of
>>>>>> the
>>>>>> problem. It is also part of ongoing research to weaken the structural
>>>>>> restrictions further, so one already knows of complete algorithms
>>>>>> that could
>>>>>> achieve this in some cases that OWL DL excludes.
>>>>>>
>>>>>> Also note that "FULL" and "DL" now refer to syntactic languages only..
>>>>>> The
>>>>>> semantic distinction is now made between "direct semantics" and
>>>>>> "RDF-based
>>>>>> semantics". This helps a bit to avoid confusion between syntax and
>>>>>> semantics. So my last remark was about finding ways to evaluate (more
>>>>>> of)
>>>>>> OWL 2 FULL under direct semantics.
>>>>>>
>>>>>> Cheers,
>>>>>>
>>>>>> Markus
>>>>>>
>>>>>>
>>>>>>  I have no hard evidence, but I feel certain that there are plenty of
>>>>>>> cases when the penalties of OWL Full are on balance small enough
>>>>>>> compared to the gains of expressive convenience and clarity of OWL
>>>>>>> Full.
>>>>>>>
>>>>>>> I would love to see someone look into this. I would love it if
>>>>>>> someone
>>>>>>> tried to create a reasoner that handled OWL Full as efficiently as
>>>>>>> possible.
>>>>>>>
>>>>>>> Notice how many responses you got to this message in the past few
>>>>>>> weeks?
>>>>>>> That may reflect how much people in the community care about OWL
>>>>>>> Full!
>>>>>>>
>>>>>>> Michael
>>>>>>>
>>>>>>> Michael
>>>>>>>
>>>>>>> On Sat, Apr 23, 2011 at 1:05 AM, Antoine Zimmermann
>>>>>>> <antoine.zimmermann@insa-lyon.fr
>>>>>>> <mailto:antoine.zimmermann@insa-lyon.fr>> wrote:
>>>>>>>
>>>>>>> Dear all,
>>>>>>>
>>>>>>>
>>>>>>> I'm looking for scientific publications related to OWL Full. I'm
>>>>>>> interested in the following kind of work:
>>>>>>> - reasoning with OWL Full;
>>>>>>> - modelling ontologies in OWL Full;
>>>>>>> - properties of OWL Full, or relationships between OWL Full and
>>>>>>> other formalisms.
>>>>>>>
>>>>>>> I've found some papers about modelling existing ontologies in OWL
>>>>>>> (for instance, modelling a UML spec or a frame-based ontology in
>>>>>>> OWL) which happen to fall into OWL Full, but nothing about modelling
>>>>>>> OWL Full ontologies by design. I found very little about reasoning
>>>>>>> in OWL Full (with the notable exception of [1], which also relates
>>>>>>> OWL reasoning to OOP).
>>>>>>> But the vast majority of papers mentioning OWL Full present it as
>>>>>>> the language that must be avoided at all cost (usually saying "if we
>>>>>>> do that, we are in OWL Full" implying "if we do that, we're
>>>>>>> screwed!").
>>>>>>>
>>>>>>> Thanks in advance for your pointers.
>>>>>>>
>>>>>>>
>>>>>>> [1] Seiji Koide and Hideaki Takeda. OWL-Full Reasoning from an
>>>>>>> Object Oriented Perspective. In R. Mizoguchi, Z. Shi, and F.
>>>>>>> Giunchiglia (Eds.): ASWC 2006, LNCS 4185, pp. 263–277, 2006.
>>>>>>> Springer-Verlag Berlin Heidelberg 2006.
>>>>>>>
>>>>>>>
>>>>>>> Regards,
>>>>>>> --
>>>>>>> Antoine Zimmermann
>>>>>>> Researcher at:
>>>>>>> Laboratoire d'InfoRmatique en Image et Systèmes d'information
>>>>>>> Database Group
>>>>>>> 7 Avenue Jean Capelle
>>>>>>> 69621 Villeurbanne Cedex
>>>>>>> France
>>>>>>> Tel: +33(0)4 72 43 61 74<tel:%2B33%280%294%2072%2043%2061%2074> -
>>>>>>> Fax: +33(0)4 72 43 87 13<tel:%2B33%280%294%2072%2043%2087%2013>
>>>>>>>
>>>>>>> Lecturer at:
>>>>>>> Institut National des Sciences Appliquées de Lyon
>>>>>>> 20 Avenue Albert Einstein
>>>>>>> 69621 Villeurbanne Cedex
>>>>>>> France
>>>>>>> antoine.zimmermann@insa-lyon.fr<mailto:
>>>>>>> antoine.zimmermann@insa-lyon.fr>
>>>>>>>
>>>>>>> http://zimmer.aprilfoolsreview.com/
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> Michael Uschold, PhD
>>>>>>> Senior Ontology Consultant, Semantic Arts
>>>>>>> LinkedIn: http://tr.im/limfu
>>>>>>> Skype, Twitter: UscholdM
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>> --
>>>>>> Dr. Markus Krötzsch
>>>>>> Oxford University Computing Laboratory
>>>>>> Room 306, Parks Road, Oxford, OX1 3QD, UK
>>>>>> +44 (0)1865 283529 http://korrekt.org/
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>> --
>>> Dr. Markus Krötzsch
>>> Oxford  University  Computing  Laboratory
>>> Room 306, Parks Road, Oxford, OX1 3QD, UK
>>> +44 (0)1865 283529    http://korrekt.org/
>>>
>>>
>>
>>
>> --
>> Michael Uschold, PhD
>>    Senior Ontology Consultant, Semantic Arts
>>    LinkedIn: http://tr.im/limfu
>>    Skype, Twitter: UscholdM
>>
>>
>
>
> --
> Michael Uschold, PhD
>    Senior Ontology Consultant, Semantic Arts
>    LinkedIn: http://tr.im/limfu
>    Skype, Twitter: UscholdM
>
>
Received on Friday, 20 May 2011 14:44:46 UTC

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