- From: Graham Klyne <GK@Dial.pipex.com>
- Date: Mon, 11 Dec 2000 00:00:26 +0000
- To: Pierre-Antoine CHAMPIN <champin@bat710.univ-lyon1.fr>
- Cc: www-rdf-interest@w3c.org
At 04:18 PM 12/8/00 +0100, Pierre-Antoine CHAMPIN wrote: > 1. the notion of stating is a useful notion, and M&S does not mention > it at all, like the authors have "forgotten" it. Since the concepts of > reified statement/stating are quite near, it is easy to interpret that > the authors... would have written "stating" if they had made the > distinction in the first place. > > 2. it is very easy to write a piece of RDF with two reified statements > being identical, and M&S does *not* make it illegal. Since a statement is > unique, it looks like a bug in the model, unless reified statements are > in fact statings. > > 3. the example for reification (namely "Ralph says that Ora was the > creator of the page") tastes just like a stating. One would like to add > the date when Ralph said that, hence the problem raised by Jonas > Liljegren : if I also want to state that "Pierre-Antoine said that Ora > was the creator of the page, at another date", then which date applies to > which stater ? > > st1: [Ora, creator, page] > st2: [st1, saidBy, Ralph] > st3: [st1, saidAt, 01/12/99] > st4: [st1, saidBy, Pierre-Antoine] > st5: [st1, saidAt, 01/12/00] > > > >Those are the main reasons I had to think that reified statements were in >fact statings. >Now, here are critics for each argument, who lead me to think maybe I was >wrong : > > about 1. That argument is not the stronger one... Actually, I would > rather stick to the spec as long as I can... So, what about 2. and 3. ? :) I agree about sticking to the spec where it is adequate to the purose concerned. > about 2. It is actually very easy to write a piece of RDF where any > resource is duplicated, not only statements. And it is not considered a > bug... although we might have troubles handling it ! Example : > > <rdf:Description about="http://www.w3.org/"> > <as:contentQuality> Excellent </as:contentQuality> > </rdf:Description> > <rdf:Description about="urn:WWWConsortium"> > <as:homepage> > <rdf:Description id="localID"/> > </as:homepage> > </rdf:Description> > <rdf:Descritpion about="mypage.html"> > <as:pointsTo rdf:resource="#localID"/> > </rdf:Description> > >where #localID and http://www.w3.org/ are in fact the same thing. Maybe I'm dense here, but I don't see the problem. > about 3. I already submitted the idea below on the list, but I will go > further : the problem raised by Jonas is not a problem ! If we do > consider that the reified statement is really a statement rather than a > stating, then the date should not be a property of st1, but rather of st2 > and st4 ! > > st1: [Ora, creator, page] > st2: [st1, saidBy, Ralph] > st3: [st2, at, 01/12/99] > st4: [st1, saidBy, Pierre-Antoine] > st5: [st4, at, 01/12/00] > >The statements st2 and st4 are actually statings, not because *every* >reified statement be a stating, but because of the particular meaning of >their predicate "saidBy". Yes, I agree. #g ------------ Graham Klyne (GK@ACM.ORG)
Received on Monday, 11 December 2000 21:24:36 UTC