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Re: defn of Named Graph

From: Gregg Reynolds <dev@mobileink.com>
Date: Thu, 19 Sep 2013 16:20:03 -0500
Message-ID: <CAO40MikCC3_8ySwgQK-sEXvAo8s1ZxmXX+mP-oC0LdJV48vPXg@mail.gmail.com>
To: Jeremy J Carroll <jjc@syapse.com>
Cc: Sandro Hawke <sandro@w3.org>, Pat Hayes <phayes@ihmc.us>, www-archive <www-archive@w3.org>
On Thu, Sep 19, 2013 at 2:35 PM, Jeremy J Carroll <jjc@syapse.com> wrote:

> Gregg I am sorry for the overly personal attack.

Very gracious of you.  Apology gladly accepted.

> I read with interest the latter part of your post concerning metonymy,
> which did seem to contrast with my (perhaps  mis)reading of the discussion
> of mathematical functions, with or without a name.
> I found it strange that Sandro responded to your message with "I'm
> probably done now. " - it struck me that Sandro was on a roll that I
> found creative.

Well, I hope he's not done.

> In particular you said:
> [[
> metonymy […] already accounts for the way RDF properties and classes are
> construed by RDF Semantics; we can just do the same thing for graphs.
> ]]
> which, if we could flesh that out, would achieve the goals I think.
> Then an RDF property is not a set of pairs, and an RDF class is not a set
> of resources, and a named graph is not a set of triples … but there is one
> step of indirection which you are referring to as being a metonym.

I would shy away from "is" and use "denotes" instead.  In my experience,
is-talk, especially in discussions about language, is often frustrating,
since "x is y" can be taken to refer either to the symbol 'x' or whatever
it denotes.  Restricting usage to either "denotes" or "refers by metonymy"
(or whatever phrase works best) avoids the ambiguity.

> How to say that in a simple ways seems to be the issue

Indeed.  I think consideration of metonymy can help clarify the issue by
relating the technical, structural aspects of RDF semantics to ordinary
natural language usage, but the term itself risks alienating at least some

Another idiom that might conceivably be useful is the distinction between
de dicto and de re interpretation. I haven't worked this out in detail, but
I think it's worth thinking about. Here's an unintentionally amusing
example (invented to illustrate the de re/de dicto disinction) from a book
published in 1994:

   The president of the United States will be black by the year 2000.

Since Bill Clinton was president in 1994, read de re this would mean "Bill
Clinton will be black by the year 2000."  Read de dicto, it means that "The
president of the United States is black" will turn out to be true by the
year 2000.  In other words, whatever it is that "The president of the US"
refers to, between 1994 and 2000 it will have been black at least once.

Now suppose we have a two names :g and :h that refer to the same graph:

   GRAPH :g { :a :b :c.}
   GRAPH :h {:a :b :c.}

And we have :g :createdBy :Jones.  On a de re reading, this would (I think)
mean Jones created {:a :b :c.}, which would entail :h :createdBy :Jones
(also on a de re reading).  But on a de dicto reading, no such entailment
would follow; it would mean something like "whatever it is that :g refers
to, was created by Jones."  Since that "whatever" might not be the graph
referred to by :h, no entailment involving :h follows.

To put it another way:  the de re reading commits the reader to the
statement that Jones created {:a :b :c}.  The de dicto reading does not.
 Example:  "The Fab Four had moptop haircuts" does not commit the de dicto
reader to the statement "The Beatles had moptop haircuts", since that
reader may not think that the Fab Four and The Beatles have the same
extension (John, Paul, George, and Ringo).  She might think the Fab Four
are the Monkees.

This account is different from the metonymy account in that it assigns no
determinate denotation/reference to :g on the de dicto reading.  We would
still have to say it denotes something in IR which maps to the graph, but
you can say something about that something without knowing its identity.
 Just like we can say "The next president of the United States will be
female" without knowing who that will be.  Or "The 12th president of the
United States was male".  I haven't the slightest idea who the 12th
president was, but I know he was male.

I'm not sure at this point if something like this works, or could be worked
into a clear and simple account that satisfies the requirements, but it
seems promising.  At the very least, you'd have to provide a way of
explicitly indicating which reading is the intended reading.


Received on Thursday, 19 September 2013 21:20:30 UTC

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