Re: mergeg in current Semantics ED

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
> >
> >
>
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