- From: Peter F. Patel-Schneider <pfpschneider@gmail.com>
- Date: Fri, 18 Jul 2014 00:49:01 -0700
- To: Jose Emilio Labra Gayo <jelabra@gmail.com>, Karen Coyle <kcoyle@kcoyle.net>
- CC: "public-rdf-shapes@w3.org" <public-rdf-shapes@w3.org>
So you are saying that ShEx is ambiguous as to whether open or closed semantics is to be applied? That seems to be a problem with the ShEx definition. peter On 07/17/2014 02:05 PM, Jose Emilio Labra Gayo wrote: > > 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 <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 <mailto:kcoyle@kcoyle.net> http://kcoyle.net > m: 1-510-435-8234 <tel:1-510-435-8234> > skype: kcoylenet > > > > > -- > Saludos, Labra
Received on Friday, 18 July 2014 07:49:32 UTC