- From: Hugh Glaser <hg@ecs.soton.ac.uk>
- Date: Wed, 30 Jun 2010 20:40:55 +0000
- To: David Booth <david@dbooth.org>, Kingsley Idehen <kidehen@openlinksw.com>
- CC: "nathan@webr3.org" <nathan@webr3.org>, Pat Hayes <phayes@ihmc.us>, Toby Inkster <tai@g5n.co.uk>, Dan Brickley <danbri@danbri.org>, Linked Data community <public-lod@w3.org>, Semantic Web <semantic-web@w3.org>
On 30/06/2010 19:55, "David Booth" <david@dbooth.org> wrote: > On Wed, 2010-06-30 at 14:30 -0400, Kingsley Idehen wrote: >> Nathan wrote: >>> Pat Hayes wrote: > [ . . . ] >>> Surely all of the subjects as literals arguments can be countered with >>> 'walk round it', and further good practise could be aided by a few >>> simple notes on best practise for linked data etc. >> >> IMHO an emphatic NO. >> >> RDF is about constructing structured descriptions where "Subjects" have >> Identifiers in the form of Name References (which may or many resolve to >> Structured Representations of Referents carried or borne by Descriptor >> Docs/Resources). An "Identifier" != Literal. >> >> If you are in a situation where you can't or don't want to mint an HTTP >> based Name, simply use a URN, it does the job. > > Can you explain *why* you think literals should not be permitted as > subjects? The rationale you have given above sounds like it is saying > that literals should not be subjects because RDF does not permit > literals to be subjects. > > IMHO, RDF should allow "anyone to say anything about anything" -- not > "anyone to say anything about anything . . . except a literal". Actually, I think it is even worse than that. RDF permits anyone to say anything about anything . . . except a literal if it is the subject of the property you want to use for the description. So I can say: foo:booth isNamed "David Booth" But of course I can't say: "David Booth" isNameOf foo:booth Now how bizarre is that? Mind you, I have sometimes wondered what happens if I try to assert something like <owl:ObjectProperty rdf:ID="isNamed"> <owl:inverseOf rdf:resource="#isNameOf"/> </owl:ObjectProperty> I guess I do not understand owl:inverseOf or that some type constraint is violated or maybe it's a RDF/OWL Full/OWL Lite issue? I also have a sense that there may be some confusion about the implications. Using a string as a subject does not imply that the string is an identifier any more than using it as an object. Of course (pace Jeremy), I don't necessarily agree that there should be any changes - we do not have sufficient Semantic Web take up that we can think of changing things without a serious discussion of costs and implications. We have gone a long way down this road managing without. Cheers Hugh > However, if you see some specific harm in permitting statements about > literals, please tell us what that harm would be. > >
Received on Wednesday, 30 June 2010 20:43:17 UTC