[Let's move this discussion to www-archive@w3.org please, as it isn't
relevant to Jeremy's comment. All follow-ups there please.]
On 09/11/2013 10:32 PM, Pat Hayes wrote:
On Sep 11, 2013, at 5:38 PM, David Booth wrote:
On 09/09/2013 02:51 AM, Pat Hayes wrote:
The question though is, whether
I(<http://my.graph.name.example.org/>) = the graph you want it
to mean. The problem is that there are people who want to use an
IRI to simultaneously denote a person (say) but also be the name
of a graph (eg of information about that person). And they have
deployed systems and much money vested in being able to do this.
Uh . . . this may be opening up a can of worms, but what you're
saying sounds a lot like the IRI resource identity ambiguity issue
that has been discussed quite a lot in the past. In short, there
is no conflict if either: (a) the class of persons has not been
asserted to be disjoint with the class of graphs
Indeed. I am assuming throughout this discussion that graphs and
persons are disjoint classes, and that this is known by all parties
involved.
Okay, but not all software needs to make that distinction. So unless it
has been explicitly stated in the graph (or implied as a valid entailment)
; or (b) the IRI denotes a person in one RDF interpretation (e.g.
in one system) but denotes a graph in a different RDF
interpretation (e.g. in a different system).
That is nonsense, as I have explained to you many times in the past.
Baloney! *Each* interpretation maps an IRI to one resource, but **RDF
ALLOWS MULTIPLE INTERPRETATIONS**! And different interpretations can
perfectly well map the same IRI to different resources. Please stop
trying to look at RDF in terms of only one interpretation! That is
*not* the only way -- or the only correct way -- to think about RDF.
Interpretations are not systems: they are alternative ways to
construe what IRIs denote.
Yes, and different systems (or people) can and do construe them differently.
But each IRI denotes one thing, in all
possible interpretations.
No, in *each* possible interpretation, not in *all* possible
interpretations. I.e.,
For any interpretation I and URIs U1 and U2,
(U1=U2) => (I(U1) = I(U1))
NOT:
For any interpretations II and I2, and URIs U1 and U2,
(U1=U2) => (I1(U1) = I2(U2))
I.e., the uniqueness does not hold *across* interpretations. It only
holds within *each* interpretation individually.
(The current RDF 1.1 semantics socument
makes thie very explicit, by the way.)
Yes, I noticed that, and the current wording is *incorrect*. It needs
to be fixed, as it wrongly implies that RDF may only be viewed from the
perspective of a single RDF interpretation, and that is simply *wrong*.
I have not yet raised that issue, but I will. I wanted to talk it
over with you first, before causing a long email thread.
If we want to allow different
occurences of an IRI to denote different things, then we would need
some kind of context mechanism in RDF, which it currently does not
have, and providing which would have been beyond this WGs charter.
You are talking about something entirely different than what I am
talking about. I am not and never have been talking about that kind of
notion of context. I am talking about the *existing* RDF Semantics, BUT
from the perspective of looking at the set of satisfying interpretations
for an RDF graph -- not from the perspective of a single interpretation.
I don't know if this observation would help resolve the problem
that you're mentioning though.
Neither of them do, I'm afraid.
Okay. I don't know enough about the graph naming debate that you
mentioned to know if it was relevant, so I'll take your word for it.
David
