- From: Andy Seaborne <andy.seaborne@epimorphics.com>
- Date: Fri, 14 Dec 2012 09:58:57 +0000
- To: Ivan Herman <ivan@w3.org>
- CC: David Booth <david@dbooth.org>, semantic-web@w3.org
On 13/12/12 20:14, Ivan Herman wrote: > > On Dec 13, 2012, at 12:42 , David Booth wrote: > [snip] >> >>> >>> The restriction of "no labels" is not just about "no cycles" - it's >>> things that are not tree-like: >>> >>> :x1 :p _:a . >>> :x2 :q _:a . >> >> Yes, excellent example. I explained to Pat in >> http://lists.w3.org/Archives/Public/semantic-web/2012Dec/0040.html >> why I chose the "no labels" restriction instead, but I'm open to >> considering either. >> > > > I think it would still be better to explain these things in a syntax independent way. After all, I may want to use JSON-LD or RDFa... > > Distilling the various mails and concentrating on bnodes only, what seems to be the pattern is > > - bnodes can appear in at most one triple as an object > - there can be no cycle in the graphs involving bnodes > > Would that suffice as a more formal definition? Yes, I think so. What about: _:a p 1 . _:a q 2 . which is [ p 1 ] q 2 . or [ p 1 ; q 2 ] . or [ q 2 ] p 1 . i.e. several forms. If the idea of a Turtle subset is using simple tools, you need to be canonical, to some extent. A possibility is that for "well formed RDF" bNodes are only for "compound values" like: :x :p [ :units :kilograms ; rdfs:value 123 ] . and ban use of [] from the subject position (because literals can't be subjects ... sorry David) Andy > > Ivan > > > ---- > Ivan Herman, W3C Semantic Web Activity Lead > Home: http://www.w3.org/People/Ivan/ > mobile: +31-641044153 > FOAF: http://www.ivan-herman.net/foaf.rdf > > > > >
Received on Friday, 14 December 2012 09:59:27 UTC