Re: Shapes/ShEx or the worrying issue of yet another syntax and lack of validated vision.

>
>
> On 7/16/14, 9:38 PM, Holger Knublauch wrote:
>
>> Most people in my experience don't care about open world semantics, but
>> of course nobody would admit that because it's against the specs and
>> thousands of academic papers.
>>
>
> The cultural heritage community cares deeply about open world semantics.
> This community has a tradition of creating primarily public-facing data
> and, even in pre-Web eras, sharing that data widely. For the cultural
> heritage community, the public, open web is the primary target for its data.
>
> You confirm for me the impression that much of the discussion here is in
> the context of enterprise data systems. I will, however, do my best to keep
> the open world visible in these discussions.


I don't think that those 2 visions (open & closed world) are incompatible.
As Kendall Clark noticed, constraint checking can also be combined with
Open World systems. One goal of Shape Expressions is to help in the
integration of heterogeneous systems in an Open World.

In fact, one of the first points in the discussion of ShEx was the
possibility to declare open shapes instead of closed ones. The difference
is that in a declaration like:

<PersonShape> { foaf:name xsd:string }

and with the triples:

:john foaf:name "John" .

:mary foaf:name "Mary";
         foaf:mbox <mailto:mary@m.com> .

a system with open shapes would assign both :john and :mary the shape
<PersonShape> because both have :foaf:name, while a system with closed
shapes would only assign :john that shape, because :mary has an extra
triple.

Eric's implementation employs Open shapes, while Shexcala first employed
closed shapes and now admits both.

In my opinion, closed shapes are good when you really need to ensure that
your graph contains some triples and only those triples, while open shapes
are better in an Open World where you want to ensure that your graph has
some shape (if it has the triples declared in the shape) but it could also
have some remaining triples.

So as a general remark, I really think the cultural heritage domain can be
a very nice use case where the needs of integrating data from different RDF
data portals appear.

Best regards, Jose Labra

>
>
> kc
> --
> Karen Coyle
> kcoyle@kcoyle.net http://kcoyle.net
> m: 1-510-435-8234
> skype: kcoylenet
>
>


-- 
Saludos, Labra