Re: SKOS Consistency

Dear Alistair:

I think that I do not explained well in my last message. Or maybe you
did not get my full message (in your reply you mentioned only the
first paragraph), because I did not say that such statements could be
inferred automatically dynamically anyway.

As indicated, the discussion referenced in
http://old.nabble.com/Dinamic-hasTopConcept-property-to26628730.html #
a26628730, I ASKED about the dynamic inference of a property
skos:hasTopConcept from the structure hierarchical relations of a
conceptual scheme.

Because the answer of that discussion and my experience during the
development of a thesaurus management system I have reached the
following conclusions:

1) The need to explicitly declare any SKOS statement (or RDF). Indeed,
the ability to make logical inferences with skos:broader and
skos:narrower is limited, (further discussion would be the same about
skos:narrowerTransitive and skos:broaderTransitive). Perhaps this
point should be a little clearer in future revisions of the SKOS
ontology.

2) On a more pragmatic sense, I think it is necessary to explicitly
define the property skos:hasTopConcept for effective consultation of
SKOS/RDF graph using SPARQL endpoints.

3) I think would be helpful that a thesaurus management software
offers the possibility of detecting a conceptual scheme has no Top
Concepts, and therefore OPTIONALLY provide its automatic creation.

As you can see we think similarly. I think that we should not consider
the execution of inferences from the SKOS model if not defined more
precisely. It is risky to leave such decisions in the hands of
automatic processes, and in any case management tools should provide
the capability to detect incompleteness in the data and automatic
creation (always supervised by the specialist).

A similar case can be found on the following statement:

<B> skos:inScheme <A>
<B> skos:broader <C>

Surely, the SKOS model does not provide mechanisms to infer the
following relationship:

<C> skos:inScheme <A>

But it might not be unreasonable that the management tool offers the
POSSIBILITY of constructing (and maintaining) such statements
automatically to facilitate management processes.

What do you think? Could be interesting for management software
provides this functionality? or should we force the expert to manually
define and maintain such statements?

Regards



El día 12 de julio de 2010 19:41, Alistair Miles
<alimanfoo@googlemail.com> escribió:
> Dear Juan Antonio,
>
> On Thu, Jul 08, 2010 at 06:58:50PM +0200, Juan Antonio Pastor Sánchez wrote:
>> Hello Quentin,
>>
>> This issue is addressed in part when I raised the possibility of
>> dynamic inference skos: hasTopConcept here:
>> <http://old.nabble.com/Dinamic-hasTopConcept-property-to26628730.html#a26628730>
>
> I am assuming that, given a graph like...
>
> <A> skos:broader <B> ; skos:inScheme <S> .
> <B> skos:inScheme <S> .
>
> ...you would like to be able to infer...
>
> <S> skos:hasTopConcept <B> .
>
> ...?
>
> If that is what you want, then note that this inference is *not* supported
> by the SKOS data model. The reason for this is ... you guessed it ... the
> open world assumption. I.e., in general, you cannot assume that you are in
> possession of all the data ... there might always be more data out there. So,
> the SKOS data model does not support any inference from the absence of data
> (in this case, from the absence of a skos:broader assertion).
>
> You are, of course, free to make whatever non-standard inferences you like,
> using whatever means, and to publish your inferences back out to the web,
> although it's best to avoid publishing data that is inconsistent with respect
> to the SKOS data model.
>
> Hth
>
> Alistair
>
>>
>> I am currently developing a thesaurus management software based on
>> SKOS and have come to the conclusion that the property must be
>> explicitly declared. My opinion is based on the subsequent operation
>> of schemes of concepts through Endpoints> <RDF using SPARQL.
>>
>> In this sense I think the management application must provide a
>> maintenance operation that allows the inference of skos: hasTopConcept
>> to allow more flexible management of a concept scheme.
>>
>> Regards
>>
>>
>> 2010/7/6 Quentin Reul <quentin.reul@tenforce.com>:
>> > Hi all,
>> > I was looking at the SKOS reference [1] and I was unable to determine
>> > whether a SKOS model would be consistent if no skos:hasTopConcept property
>> > was defined within a concept scheme.
>> > Cheers,
>> > Quentin
>> > [1] http://www.w3.org/TR/skos-reference
>> >
>> > --
>> > Quentin Reul
>> >
>> > Semantic Technology Consultant
>> > TenForce BVBA
>> > Haachtsesteenweg 378
>> > 1910 Kampenhout
>> > Belgium
>> >
>>
>>
>>
>> --
>> Ph.D. Juan Antonio Pastor Sánchez
>> Dep. of Information and Documentation
>> Faculty of Communication and Documentation
>> University of Murcia
>> phone: +34 868 88 8780
>> http://webs.um.es/pastor
>> pastor@um.es
>>
>
> --
> Alistair Miles
> Centre for Genomics and Global Health <http://cggh.org>
> The Wellcome Trust Centre for Human Genetics
> Roosevelt Drive
> Oxford
> OX3 7BN
> United Kingdom
> Web: http://purl.org/net/aliman
> Email: alimanfoo@gmail.com
> Tel: +44 (0)1865 287669
>



-- 
Ph.D. Juan Antonio Pastor Sánchez
Dep. of Information and Documentation
Faculty of Communication and Documentation
University of Murcia
phone: +34 868 88 8780
http://webs.um.es/pastor
pastor@um.es

Received on Monday, 12 July 2010 18:25:31 UTC