Re: On linking vocabularies (Was: SKOS for schema.org proposal for discussion)

Hello all

Just to say +1 to schema:sameAs being kept as scruffy as it is, and at the
light of this discussion, revisit its definition ...
"URL of a reference Web page that unambiguously indicates the item's
identity. E.g. the URL of the item's Wikipedia page, Freebase page, or
official website."
... *unambiguously* is certainly too strong and should be removed from the
definition because it conveys some notion of certainty about identity which
will never be achieved either in theory [1] or in practice (as the current
discussion illustrates once again).

Bernard

[1] http://plato.stanford.edu/entries/identity-relative/



2013/10/14 Antoine Isaac <aisaac@few.vu.nl>

> Hi,
>
> Sure, I think I agree. I might have expressed myself quite wrongly in
> fact. I meant to say that I was happy with the under-specification of
> schema:sameAs, and that this under-specification could actually allow to
> capture some of the semantics of skos:exactMatch, which is not itself a
> monster of formal axiomatization.
>
> Antoine
>
>
>  We can define terms as precisely as we would like, but in the end, the
>> meaning is in the usage. And in practice, webmasters cannot be expected to
>> dive into nuances as much as this group does (or would like them to).
>>
>> And in a super distributed system like the web, we can be very very sure
>> that almost every integrity constraint will be violated!
>>
>> guha
>>
>>
>> On Mon, Oct 14, 2013 at 2:25 AM, Antoine Isaac <aisaac@few.vu.nl <mailto:
>> aisaac@few.vu.nl>> wrote:
>>
>>     Hi Jeff,
>>
>>     I think Niklas' original email was about to assert equivalences
>> between classes or properties between SKOS and schema.org <
>> http://schema.org>, not equivalences at the level of instances (of skos:
>> or schema:Concept).
>>
>>
>>     Now, there's some value discussing how to represent what in SKOS is
>> represented as skos:exactMatch (at the level of Concept instances). As you
>> hint, this one was introduced because the strict semantics of owl:sameAs
>> didn't fit the kind of softer equivalence cases we wanted to capture. And
>> be compatible with a couple of constraints.
>>
>>     But in fact schema:sameAs [1] is quite different from owl:sameAs, and
>> it could be good. In fact at the time Jean can with the proposal I was
>> involved with, [1] was not existing. It may be worth dropping a line in the
>> new wiki page for the proposal, saying whether we regard schema:sameAs a
>> good property to use for skos:exactMatch.
>>
>>     (this in practice would amount to declare
>>     skos:exactMatch rdfs:subProperty schema:sameAs
>>     which brings us back to the original linking level that Niklas wanted
>> ;-) )
>>
>>     Cheers,
>>
>>     Antoine
>>
>>     [1] http://www.w3.org/wiki/__**WebSchemas/sameAs<http://www.w3.org/wiki/__WebSchemas/sameAs><
>> http://www.w3.org/wiki/**WebSchemas/sameAs<http://www.w3.org/wiki/WebSchemas/sameAs>
>> >
>>
>>         Hopefully, Schema.org<http://Schema.org> won't carry-forward
>> some of the SKOS constraints in its "equivalent" terminology (whatever that
>> ends up being). For example, it is a SKOS S14 constraint violation to say
>> that the LCSH concept of World War 2 (http://id.loc.gov/__**
>> authorities/subjects/__**sh85148273<http://id.loc.gov/__authorities/subjects/__sh85148273><
>> http://id.loc.gov/**authorities/subjects/**sh85148273<http://id.loc.gov/authorities/subjects/sh85148273>>)
>> is "the same as" the DBpedia concept (http://dbpedia.org/resource/_**
>> _World_War_II <http://dbpedia.org/resource/__World_War_II> <
>> http://dbpedia.org/resource/**World_War_II<http://dbpedia.org/resource/World_War_II>
>> >).
>>
>>
>>
>>         On those rare occasions where the distinction matters, SKOS
>> should be used. Most cases, though, shouldn't need this fussiness.
>>
>>         Jeff
>>
>>
>>
>>
>
>


-- 
*Bernard Vatant
*
Vocabularies & Data Engineering
Tel :  + 33 (0)9 71 48 84 59
Skype : bernard.vatant
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