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Jonathan Borden wrote:
> I assume you are saying that XSD can do -without- types, and to the extent
> that XSD is used as a language to express -syntactic constraints- on unicode
> strings, this is certainly true. The point of semantics is that now that we
> have a piece of XML that let's say corresponds to some RNG pattern or XSD
> type _now what_. How can we specify how different programs i.e. processes
> might use this piece of XML in an interoperable fashion.
The answer is to your question is simple where we're using
ontologies. Have a model-theory (there's no other game in town). But
that's not sufficient to get something useful done.
On looking at a sentence inscribed in a language and trying to
understand what it means (so as to act as the writer intended),
that's pragmatics, not semantics. For the semantic web to have
pragmatics (and literally, to be practical), you want a combination
of protocol (a sequence of speech acts) and ontology (term grounding
for the content expressed). For interoperability both protocol and
act need to be agreed or an agreement easily derived. There are
issues with that view, naturally enough.
Btw, the only set of specifications (imo) that are coherent and
complete in this regard are FIPA's. The W3C work is scattergun by
comparison (sometimes I wonder if the semantic and protocol sides of
that house are on speaking terms).
> Penicillin 500mg p.o. q.i.d. x 3 weeks.
> (assume an XML encoding of that since we are xml-dev here)
> I want to be very precise about what happens when this message is sent to
> the pharmacy -- at least as precise as the current situation when I write
> this down on a slip of paper and transmit the message via sneakernet.
To be specific and avoid handwaving about the S-word. Semantics has
to do with the intepretation of the language we're using to write
things down. The penicillin example above doesn't have a semantics,
it's a sentence, but the language you wrote it in might, and that's
probably useful if all the actors are both rational and agree to
terms. That's a boring technical defintion of Semantics, but at
least it makes it distinct from wondering about what some piece of
markup might mean to an actor.
Bill de hÓra