Re: How do you deprecate URIs? Re: OWL-DL and linked data

Hi Giovanni,

Some more thoughts :-)

>then there is http://geonames/123456 that might also be berlin.  If
>there is an agreement by the dbpedia guys that that entity is
>equivalent for DBPEDIA PURPOSES to their entities then the dbpedia
>people put a "sameAs" between the two. So "sameAs" on the web of
>linked data is always a "directed sameAs"

>This pragmatic interpretation should be "we people at dbpedia believe
>that it might be useful for you as a robot to also go collect
>information from this other source as we find it generally compatible
>with the information we provide here"


When it comes to linking data, I guess it is important to agree upon the 
following three points:

1. Perfect equivalence is extremely rare. The more closely you look, the 
more likely is that you spot differences. So there are very few pairs of 
URIs that one could actually link by sameAs, equivalentClass, etc.

2. Weaker relations of equivalence that hold universally are practically 
useless. In the end, those relations that are true for everybody, for 
every purpose, at any time are so relaxed that they are useless in 
processing the data. In the end, they would just be association relations.

3. For practical impact, we must (and do so every day outside the SW 
box) adopt stronger statements of equivalence, such that may not hold 
universally, but are appropriate for our context of usage and purpose. 
So we assume things to be more similar than they actually are (btw, this 
is the core principle of classification).

4. We can only learn of and validate similarity between identifiers by 
joint action - joint communication or other joint action. For example, 
we only know whether we referred to the same location in making an 
appointment if we actually meet there. This idea is based on the 
"Pragmatic Semantic Unification" idea by Charles Petrie.

Best
Martin
-----------------------------------------------
martin hepp,  http://www.heppnetz.de
skype mfhepp, mhepp@computer.org

Giovanni Tummarello wrote:
>> "http:..." or something equivalent, not a reference <http:...>, since in the
>> latter case you're talking about what the URI names, not the URI itself, and
>> things can have more than one name - some of which might be deprecated, and
>>     
>
> Some thoughs:
>
> Pragmatically speaking if there is one thing that "linked data" buys
> us is new URIs for the same thing others might be talking about, but
> specifically minted within "one's context", that is the name space of
> the site who's hosting the RDF
>
> so http://dbpedia.org/resource/Berlin is really not "berlin" in
> general but obviously "something that they have in their DB that has
> label "berlin" and bla bla
>
> then there is http://geonames/123456 that might also be berlin.  If
> there is an agreement by the dbpedia guys that that entity is
> equivalent for DBPEDIA PURPOSES to their entities then the dbpedia
> people put a "sameAs" between the two. So "sameAs" on the web of
> linked data is always a "directed sameAs"
>
> This pragmatic interpretation should be "we people at dbpedia believe
> that it might be useful for you as a robot to also go collect
> information from this other source as we find it generally compatible
> with the information we provide here"
>
> given this interpretation of "linked data URIs" (something i
> previously called URI/URLs and i still dont find a better term for it)
> then i believe its perfectly valid to state things about the URI
> itself, since they always must be interpreted within the context where
> they were taken.
>
> i know, OWL doesnt account for this, that is, it will not make
> distinctions between "context only valid statements" and not.. but i
> see no alternative to deal with this at preprocessing level, e.g. when
> you crawler picks up linked data information, you should look for said
> context onyl valid statments before you smush all together with the
> sameAs
>
> Giovanni
>
>
>   

-- 

-----------------------------------
martin hepp, http://www.heppnetz.de
mhepp@computer.org, skype mfhepp