- From: Pat Hayes <phayes@ihmc.us>
- Date: Fri, 23 Nov 2012 16:14:51 -0800
- To: Jan Wielemaker <J.Wielemaker@vu.nl>
- Cc: Tim Berners-Lee <timbl@w3.org>, <nathan@webr3.org>, Richard Cyganiak <richard@cyganiak.de>, Guus Schreiber <guus.schreiber@vu.nl>, RDF WG <public-rdf-wg@w3.org>
On Nov 22, 2012, at 12:26 AM, Jan Wielemaker wrote: > I guess we should not (re)start this discussion unless there is > a concrete proposal to introduce strings as subjects. My quick > intuition is that these are a few of the consequences that I don't > like. > > - Invites for poor modelling I have never found the suggested examples compelling, but in any case, this should be handled by good-use guides and tutorials rather than hardwired into the syntax. > - Introduces interoperability issues How so? (Do you mean with legacy systems: well yes, of course. But any change can be objected to on those grounds.) > - Harms efficient reasoning. One of the nice things about > resources is that you can compare them quickly. SPARQL > Lit1 = Lit2 is a much more complicated beast. Incomprehensible. Equality between literals is if anything easier to compute than between IRIs. The problem of establishing owl:sameAs between two IRIs is probably worse then NP-complete. Pat > > --- Jan > > > On 11/21/2012 08:05 PM, Tim Berners-Lee wrote: >> >> Literals in the *subject* position, on the other hand -- are very sensible. >> I have listed reason for these before, and the discussion must be very >> old so I'm >> not inclined to go into them in great depth. >> >> "Fr." :isShortFor "France". >> >> 3 expressedAsAString "3". >> >> 12 :mutuallyPrime 35. >> >> "chat" :occursIn :English, :French. >> Also we have inverses, which make any asymmetry >> in what can be put in S and O positions lead to strange things, >> >> :foo :seconds 73. >> :second owl:inverse :hertz. >> >> for example can be said but leads to an inference which >> cannot be expressed if you can't put a number as a subject. >> >> Tim >> >> On 2012-11 -19, at 13:20, Jan Wielemaker wrote: >> >>> On 11/19/2012 07:13 PM, Pat Hayes wrote: >>>> How about literals in subject position in a triple? >>> >>> I think it is the same story. Invites for >>> >>> "Paris" something:catipalOf "France" >>> >>> While we all know there are other ways to interpret >>> "Paris". >> >> Yes, but I think your example makes clear: >> What on earth makes you suppose form this example that >> there is any difference between the needs for subject and the needs for >> objects? >> >> Clearly, by this thinking, literals should due dial allowed in the >> object position too! >> >> >> >> >> >>> I think we are doing right to allow for >>> literals only in the object position. >>> >>> Cheers --- Jan >>> >> > > ------------------------------------------------------------ IHMC (850)434 8903 or (650)494 3973 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32502 (850)291 0667 mobile phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes
Received on Saturday, 24 November 2012 00:15:24 UTC