- From: Andy Seaborne <andy.seaborne@epimorphics.com>
- Date: Sat, 15 Dec 2012 17:39:41 +0000
- To: semantic-web@w3.org
On 14/12/12 21:06, Ivan Herman wrote: > > On Dec 14, 2012, at 02:45 , Ivan Shmakov wrote: > >>>>>>> Ivan Herman <ivan@w3.org> writes: >>>>>>> On Dec 13, 2012, at 12:42 , David Booth wrote: >> >> […] >> >>>>> 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 >> >> AIUI, this restriction was added merely to allow for a simpler >> WB-RDF definition. It wouldn't be necessary should Turtle have >> included a “inverse property” syntax. (Which I doubt it'll >> acquire in a foreseeable future.) >> > > You are right, it will not... The current Turtle will go to CR soon (ie, early next year) (hypothetically speaking) It depends on what is the "subject" :-) If inverse properties are just surface syntax, it would be appropriate to use language like to talk inverse properties like: object ^property subject so the subject is still "the subject" of a triple. Andy > > >> However, as I've noted earlier, when this restriction is in >> effect, it's simple to assign (semi-)unique identifiers to all >> the blank nodes, based solely on their relation to the other >> nodes. (Provided that the next criterion is also met.) >> >>> - there can be no cycle in the graphs involving bnodes >> >> I believe that the point was that there'd be no cycles >> consisting /exclusively/ of bnodes. > > Right, I was sloppy. See my reply to David... > > Ivan > > >> >>> Would that suffice as a more formal definition? >> >> -- >> FSF associate member #7257 >> >> > > > ---- > 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 Saturday, 15 December 2012 17:40:09 UTC