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Re: RE : [SKOS] the return of transitive and subproperty (was Re: SKOS comment: change of namespace (ISSUE-117))

From: Simon Spero <ses@unc.edu>
Date: Thu, 31 Jul 2008 10:10:27 -0400
Message-Id: <A306C719-3036-49F1-A49D-E42A7069EB0E@unc.edu>
To: Stephen Bounds <km@bounds.net.au>
Cc: Antoine Isaac <Antoine.Isaac@KB.nl>, SKOS <public-esw-thes@w3.org>

If you don't inference all you will see are the direct links; it's an  
application specific inferencing issue. Polly hierarchy doesn't affect  
this (see Soergel , etc

If all links are BT, it must be the case that everything about Emus  
must be about Animals. Otherwise at least one link on the path *must*  
be associative.

Simon

Sent from my iPhone

On Jul 31, 2008, at 9:43 AM, Stephen Bounds <km@bounds.net.au> wrote:

> G'day Simon,
>
> I understand what you're saying, but that is not really my objection.
>
> If someone wants to implement a polyhierarchical thesaurus, then  
> this kind of structure is quite common:
>
>       Animals
>          |
>          |
>        Birds
>         |  \
>         |   \
>         |   Australian Birds
>         |    |       |
>         |    |       |
>        Cockatoos    Emus
>
> If <skos:broader> is non-transitive, then there is a single,  
> unambiguous way to represent this hierarchy.
>
> But if <skos:broader> is transitive, then asserting
>
>  Cockatoos skos:broader Birds
>
> does *not* tell us whether the author intends a direct link between  
> Cockatoos and Birds in the hierarchy.
>
> Now, from a semantic reasoning point of view, the presence or  
> absence of this parent-child link is irrelevant:  'Birds' is broader  
> than 'Cockatoos' in either case.
>
> But it's *not* irrelevant in terms of how the thesaurus gets  
> presented to an end-user, and that's precisely my point.
>
> Regards,
>
> -- Stephen.
>
> Simon Spero wrote:
>> Stephen-
>> If you aren't using a reasoner, then you don't need to start doing  
>> so to introspect and undo the effects of using... a reasoner.
>> If you are working with an rdf suite like Redland, and don't hook  
>> it up to an inference engine, you just get the direct assertions.
>> You don't have to draw every conclusion entailed by ones knowledge  
>> base; the black lump lying on my feet is ki-chan. I do not need to  
>> access the fact that he is a eukaryote to know he's being friendly  
>> because he wants second breakfast; I only need to know that he's a  
>> cat.
>> It's when you *publish* data that you need to take care not to use  
>> hierarchical relations in cases where the link is not truly  
>> hierarchic.
>> Simon
>> Sent from my iPhone
>> On Jul 31, 2008, at 5:22 AM, Stephen Bounds <km@bounds.net.au> wrote:
>>>
>>> Hi Antoine,
>>>
>>> Yes, I am in favour of the current SKOS version.
>>>
>>> I strongly believe SKOS is most likely to see broad uptake if  
>>> people *don't* need SPARQL or some other RDF query dialect to do  
>>> useful things with it.
>>>
>>> Cheers,
>>>
>>> -- Stephen.
>>>
Received on Thursday, 31 July 2008 14:11:09 GMT

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