W3C home > Mailing lists > Public > public-rdf-wg@w3.org > March 2013

Re: mergeg in current Semantics ED

From: Peter Patel-Schneider <pfpschneider@gmail.com>
Date: Thu, 7 Mar 2013 14:25:34 -0800
Message-ID: <CAMpDgVxeW=R6RgMsJ=tC=y9OCN9KTQAig0biLYV1OZbvNdU3xw@mail.gmail.com>
To: Pat Hayes <phayes@ihmc.us>
Cc: Antoine Zimmermann <antoine.zimmermann@emse.fr>, RDF WG <public-rdf-wg@w3.org>
I think that the current document makes the entailment not work.

G1 is Ex p1(s1,x)
G2 is Ex p2(s2,x)

{G1,G2} is Ex p1(s1,x) ^ p2(s2,x)

In particular, {G1,G2} is *not* Ex p1(s1,x) ^ Ex p2(s2,x)

peter


On Thu, Mar 7, 2013 at 12:51 PM, Pat Hayes <phayes@ihmc.us> wrote:

>
> On Mar 7, 2013, at 12:30 PM, Peter Patel-Schneider wrote:
>
> >
> >
> > On Thu, Mar 7, 2013 at 10:22 AM, Pat Hayes <phayes@ihmc.us> wrote:
> >
> > On Mar 7, 2013, at 9:52 AM, Antoine Zimmermann wrote:
> >
> > > There is a problem with the definition of merge in the draft.
> > >
> > > I'm using math notations instead of a concrete serialisation syntax
> because I want to show things at the abstract syntax level, which is what
> RDF Semantics relies on.
> > >
> > > Let us take a blank node b from the set of blank nodes. Let us
> consider the two graphs G1 = {(<s1>,<p1>,b)} and G2 = {(<s2>,<p2>,b)}.
> >
> > You have the same bnode in both graphs, so they must be in the same
> scope, right? For example, both are subgraphs of a larger graph, or both in
> the same dataset.
> >
> > >
> > > Let us ask ourselves whether {G1,G2} entails:
> > >
> > > G = {(<s1>,<p1>,b),(<s2>,<p2>,b)}
> > >
> > > The answer is trivially NO wrt the current semantics of the ED.
> >
> > If those really are the same b, then the answer is YES, and I claim that
> it should be.
> >
> >
> > I don't know how you are going to get this to go through.
>
> Do you mean, technically or politically? Technically, this is true now
> (that G1 and G2 together entail G) and it also was in the 2004 semantics,
> if the G1 and G2 were for example subgraphs of G. Politically, I think we
> have debated this to death and the new account based on scopes is exactly
> what the WG wants. For example, we have an explicit decision that all
> bnodes in (all graphs in) a dataset shall share bnodes in common, so to
> standardize those bnodes apart would be definitely a mistake.
>
> Pat
>
>
> >
> > peter
> >
> >
>
> ------------------------------------------------------------
> 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 Thursday, 7 March 2013 22:26:01 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 16:25:54 GMT