Re: MISC: Internet Media Type registration: proposed TAG finding

On Wed, 2002-05-29 at 11:35, patrick hayes wrote:
[...]
> >It wouldn't be unprecedented, by the way:
> >
> >   http://www.w3.org/2000/10/swap/log#Truth
> 
> Wow, scales fall from my eyes!

Why is this so crazy? It doesn't seem interestingly
different from wtr in KIF.

[...]
> Seriously, that document (1) does not define logical truth in any way 
> whatsoever (2) says this: - <rdfs:Class 
> rdf:about="http://www.w3.org/2000/10/swap/log#Truth">
>    <rdfs:comment>Something which is true: belive it as you would 
> belive this. Understood natively by cwm in that it will execute rules 
> in a formula declared a Truth within a formula it is already taking 
> rules from.</rdfs:comment>
> 
> which seems to indicate that log#Truth in fact is simply supposed to 
> mean 'asserted', which is perfectly meaningful, but is not the same 
> as 'logically true'.

Er... close to that; it's a de-quoting mechanism.


> And in fact, the document does not define *any* 
> meanings in RDF, or constrain the RDF interpretations, in any way 
> whatsoever. It is just English with RDF decorations added. (The CWM 
> code might be said to be a kind of implicit machine-readable 
> constraint on interpretations of this vocabulary - along the lines of 
> 'this means whatever it takes to make CWM produce valid conclusions' 
> - but it goes well beyond what an RDF engine would be able to make 
> use of.)

[...]
> >>  Who discovers this, and how? 
> >
> >As explained above, I (i.e. anybody using
> >the framework) use the deployed URI infrastructure
> >to dereference http://www.daml.org/2001/03/daml+oil#UniqueProperty
> >and I see:
> >
> ><rdfs:Class rdf:ID="UniqueProperty">
> >   <rdfs:label>UniqueProperty</rdfs:label>
> >   <rdfs:comment>
> >     compare with maxCardinality=1; e.g. integer successor:
> >     if P is a UniqueProperty, then if P(x, y) and P(x, z) then y=z.
> >     cf OIL FunctionalProperty.
> >   </rdfs:comment>
> >   <rdfs:subClassOf
> >rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Property"/>
> ></rdfs:Class>
> >
> >The comment there is reasonably clear as a constraint
> >on interpretations, no?
> 
> NO!!! It is not in any way a constraint on interpretations, any more 
> than a comment in a program is code.

How is that not acceptable as a constraint on interpretations, but
stuff like this is?


[[
for ?D an XML Schema datatype, IO(?O) is the singleton set containing
the element of IC(?D) that has lexical representation ?L, provided that
there is one, otherwise IO(?O) = { }
]]
 -- http://www.w3.org/TR/2001/NOTE-daml+oil-model-20011218#3



> A comment is a COMMENT, and that 
> is all. YOU can read that and understand it, Dan, because you are a 
> HUMAN BEING WHO UNDERSTANDS ENGLISH. The whole point of the semantic 
> web is to allow SOFTWARE AGENTS to do a little understanding.

Yes, so, I read the comment and write some code.

> When 
> you can write a Perl script that can figure out the content of the 
> English comments, then maybe you can claim that the meaning of the 
> comments is part of the meaning of the formalism. It still wouldn't 
> be part of RDF, but you could call it RDFE .

It seems to me to be a perfectly reasonable part of
the Resource Description Framework. I guess I'm willing
to call it an extension to RDF, if that makes you happy.
But it seems pretty arbitrary, to me.


[...]
> >Let's put it this way: does dublin core fit into the framework?
> >Or is RDF+dc an extension? How about a document that
> >uses RDFS, DAML+OIL, and dublin core together? Is that
> >another sort of extension?
> 
> Dan, you cannot possibly be this obtuse. Surely you know the 
> distinction between a language and a set of axioms in that language. 
> DC is a set of assertions in RDF, right?

No; it's a set of terms defined by a community of practice.

There are semantics to the dublin core terms that aren't
written in the RDF specs.

> That means that one can 
> interpret those DC assertions using the RDF semantics and they mean 
> something that approximates to what the DC writers had in mind, 
> roughly. If you do that to DAML, you often *don't * get an 
> approximation of what the writer of the DAML had in mind.

I must be quite obtuse; I don't see any fundamental
difference between partial understanding of DC semantics
and partial understanding of DAML semantics.

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/

Received on Thursday, 30 May 2002 18:20:57 UTC