- From: Pierre-Antoine Champin <swlists-040405@champin.net>
- Date: Fri, 28 Mar 2008 17:59:17 +0100
- To: Alan Ruttenberg <alanruttenberg@gmail.com>
- Cc: Olivier Rossel <olivier.rossel@gmail.com>, semantic-web@w3.org
Alan Ruttenberg a écrit : > > A hack it is, because the reifications have no semantic implications for > the original triple according to the RDF semantics. anyway, RDF semantics has no immediate support for temporality (i.e. a triple is valid at some point in time, invalid at another). so if you want to reason with this kind of things, it *has* to be some kind of meta-reasoning "above" classical RDF reasoning. of course, you can decide to use RDF to do that meta-reasoning, and this is where reification comes handy (to distinguish, in the "meta" layer, meta-statements from "lower" statements). so in my point of view, this is not a hack -- not in the negative sense you seem to imply, anyway ;) pa > -Alan > > On Mar 28, 2008, at 6:36 AM, Olivier Rossel wrote: > >> >> you can hack conditional statements in RDF with reification. >> cf http://lists.w3.org/Archives/Public/semantic-web/2008Mar/0085.html >> >> On Fri, Mar 28, 2008 at 10:58 AM, Phil Archer <parcher@icra.org> wrote: >>> >>> Being the one who kicked this off by making the original assertion >>> (which I actually got from someone else but almost certainly >>> mis-interpreted along the way) I feel I should give a little further >>> input. >>> >>> Actually, it's _good news_ (as well as common sense) that triples don't >>> get stored in perpetuity. I came to this from the standpoint of wanting >>> to make the statement (in a semantic way) that >>> >>> foaf:Agent "will stand by the following assertions until" $date >>> >>> Which is a little different from a cache header... >>> >>> Phil. >>> >>> >>> >>> Renato Golin wrote: >>>> >>>> Phillip Rhodes wrote: >>>>> In a discussion that has arisen recently on the foaf-dev list, >>>>> somebody >>>>> pointed out that they've been told that RDF triples live forever. >>>>> That is, once something is asserted it is considered asserted until, >>>>> as it >>>>> was put, "the entropic heat death of the universe." >>>> >>>> Hi Phillip, >>>> >>>> This assertion is, to me, the same as to say all web pages are static, >>>> meaning that you can cache them locally without any further attempt to >>>> get it back from the server again. >>>> >>>> All web browsers have a fair cache policy which we're all used to >>>> (Shift-F5 and stuff) so no big deal to do the same with triples and RDF >>>> browsers. >>>> >>>> Also, with RDF is easier to say that site A has "the same triple as" >>>> another site B but with different content, who will you trust? Let's >>>> say >>>> you have a timestamp annotating the triples, would you still believe >>>> the >>>> "newest" one? >>>> >>>> Site A: >>>> renato is bad (today) >>>> >>>> Site B: >>>> renato is good (10 years ago) >>>> >>>> It's the same with RDFAuth, you have to trust someone sometime, you >>>> need >>>> a list of trusted sites, people, documents, beliefs. If your site says >>>> "renato is bad" it may "like" better Site A and even automatically add >>>> it to the "trusted sites" or even keep a score of things you agree with >>>> the site as the "automatic trust level" as opposed to your "hardcoded >>>> trust level" when you trust someone even if you don't agree with >>>> him/her. >>>> >>>> The possibilities are endless... >>>> >>>> cheers, >>>> --renato >>>> >>>> >>>> >>> >>> -- >>> Phil Archer >>> Chief Technical Officer, >>> Family Online Safety Institute >>> w. http://www.fosi.org/people/philarcher/ >>> >>> >>> >>> >>> >> > >
Received on Friday, 28 March 2008 17:00:12 UTC