Re: Publications about OWL (1 or 2) Full

Thanks for a thorough reply.  See comments inline.

On Thu, May 19, 2011 at 3:09 AM, Markus Krötzsch <
markus.kroetzsch@comlab.ox.ac.uk> wrote:

> On 18/05/11 19:49, Michael F Uschold wrote:
>
>> These are good questions. You are right, the current attitude and
>> practice is avoid OWL Full at all costs.  Unfortunately, this ignores
>> the costs of NOT using OWL Full -- basically it means having to do a lot
>> of painful workarounds that make the ontology harder to understand which
>> undermines one of the key goals of ontology: to make meaning clear!
>>
>> If you want to be able to have meta classes, and use classes as values
>> for properties and other OWL Full goodies, you have to use a more
>> powerful reasoner. Any FOL prover would do, I should think, but I am no
>> expert.
>>
>
> 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.

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.

I also do not think there is a robust solution to the 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?


> 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.


>
> 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/
>



-- 
Michael Uschold, PhD
   Senior Ontology Consultant, Semantic Arts
   LinkedIn: http://tr.im/limfu
   Skype, Twitter: UscholdM