- From: Danny Ayers <danny.ayers@gmail.com>
- Date: Fri, 15 Jan 2010 21:20:21 +0100
- To: Toby Inkster <tai@g5n.co.uk>
- Cc: jeremy@topquadrant.com, "semantic-web@w3.org" <semantic-web@w3.org>
Thanks Toby, that's compelling enough for me. 2010/1/15 Toby Inkster <tai@g5n.co.uk>: > On Fri, 2010-01-15 at 11:57 +0100, Danny Ayers wrote: >> Aside from a little tidiness, what would we actually gain through >> going the whole hog on what can go in which position in the triple? >> >> blank node predicate - what does that tell you that an rdfs:seeAlso >> wouldn't? > > <#school> > [ > rdfs:subPropertyOf ex:teacher ; > rdfs:label "maths teacher" ; > ex:relatedTopic dbpedia:Mathematics > ] > <#joe> . > > <#band> > [ rdfs:subPropertyOf foaf:member ; ex:relatedInstrument <#bongo> ] > <#jim> . > > These structures are of course already permissible in RDF, but only if > you're willing to commit to giving the property a URI. > >> literal subject - aside from quotations: >> >> "I can't really see how it would be useful" <x:saidBy> <#me> . > > If the above was the only use case, then it would not be especially > useful - you'd simply create a x:didSay predicate that worked in the > reverse direction. With blank node predicates that's even easier: > > <#me> > [ owl:inverseOf x:saidBy ] > "I can't really see how it would be useful" . > > But that's not the only use case. Consider relationships between two > literals: > > "Toby Inkster" foaf:sha1 "4296ab2b2243bdb1e3cd1952158d2ce5464ea10c" . > > I can imagine wanting to do things like: > > SELECT ?person ?hash > WHERE { > ?person ex:password ?pwd . > ?pwd foaf:sha1 ?hash . > FILTER (?hash = "672059bd1419f8b90633fc2d02529be0de2fa614") > } > > Both blank node predicates and literal subjects are already allowed by > N3 and are theoretically allowed by SPARQL (though I don't know of any > implementations that choose to support them). > > -- > Toby A Inkster > <mailto:mail@tobyinkster.co.uk> > <http://tobyinkster.co.uk> > > -- http://danny.ayers.name
Received on Friday, 15 January 2010 20:20:56 UTC