- From: Pat Hayes <phayes@ihmc.us>
- Date: Thu, 22 Nov 2018 15:00:20 -0600
- To: Dan Brickley <danbri@danbri.org>, Martynas Jusevičius <martynas@atomgraph.com>
- Cc: martige@ifi.uio.no, Semantic Web <semantic-web@w3.org>
On 11/22/18 9:30 AM, Dan Brickley wrote:> This did crop up in json-ld, see > https://github.com/w3c/json-ld-syntax/issues/37 with the notion > of "generalized rdf" introduced in the last round of specs. > https://www.w3.org/TR/rdf11-concepts/#section-generalized-rdf > > > > > On Thu, 22 Nov 2018, 06:20 Martynas Jusevičius > <martynas@atomgraph.com <mailto:martynas@atomgraph.com> wrote: > > Is that really an essential problem? With blank nodes as > predicates, > will it suddenly become easier to build RDF applications and > explain > it "for dummies"? > > A lot of infrastructure will break and/or will have to be > updated, > that is for sure. FWIW, allowing bnodes in predicate position (and literals in subject position) does not affect the RDF semantics at all. The 2014 RDF 1.1 semantics specification applies to generalized RDF syntax without changing a single word. Infrastructure which checks for conformance to RDF syntax would need to be changed, obviously, but the changes should be minimal as they simply amount to not performing certain syntax checks which are currently required. Inference engines which perform any kind of unification should generalize to the more liberal syntax with minimal changes to code, although indexing and hashing might need more substantial changes. But any RDF inference engine which is complete will probably be already using generalized RDF syntax, or something equivalent, internally. Basically, it would be a lot easier than many people think. Pat Hayes > <martige@ifi.uio.no <mailto:martige@ifi.uio.no>> wrote: > > > > On 22/11/18 13:02, Tim Berners-Lee wrote: > > >> On 2018-11 -21, at 22:40, David Booth wrote: > > > > >> Blank nodes are special second-class citizens > > >> in RDF. They cannot be used as predicates, > > > > > > Agreed it messes up the symmetry. Actually in most of > my code you can > > > use a blank node as a predicate. That said, RDF is > unusual in having as > > > much symmetry. > > > > I like symmetry. Can we get a ✅ for blank nodes as > predicates too? ✅ > > > > Martin > > > -- ----------------------------------- call or text to 850 291 0667 www.ihmc.us/groups/phayes/ www.facebook.com/the.pat.hayes
Received on Thursday, 22 November 2018 21:00:56 UTC