[sc34wg3] a TM Application Definition example

[Martin Bryan]

Steve (N):

I don't think the following analogy is correct, or very helpful.

> A Topic Map Application Definition is analogous to a Document Type
> Definition.  Both can serve as a basis for interchanging information
> between people who wish to interchange that kind of information.

Objective i) of ISO 8879 clearly stated "The markup must be usable by both
humans and programs." TMA clearly violates the last two words of this
statement. Until TMAs are usable by programs it is my opinion that they do
not and cannot serve the same purpose as a DTD.

> SGML/XML serves as a foundation for a paradigm in which a single
> parsing discipline -- variously implemented in various technologies --
> allows information expressed in an unbounded number of syntaxes,
> representing an unbounded number of semantics, to be interchanged in
> conformance with that single parsing discipline.  The author of an
> SGML/XML document that conforms to some SGML/XML syntax can reasonably
> expect everyone in the world to get exactly the same results -- always
> the same parse tree -- from any conforming parser.

This is the true goal of ISO 8879: ensuring that the parse tree provided as
the result of parsing an encoded file according to the rules specified in a
given concrete syntax was the same.

The author of a TMA specification that conforms to some TM syntax should
reasonably be able to expect every TM conformant system to provide him
access to the same set of information that can be queried with the TM Query
Language. This should be our paramount goal in creating models for topic
maps.

> Similarly, the TMM serves as a foundation for a paradigm in which a
> single processing discipline -- variously implemented in various
> technologies -- allows any topic map, expressed in any syntax,
> representing an unbounded number of semantics, to be interchanged in
> conformance with that discipline.  The author of a topic map can
> reasonably expect everyone in the world to get exactly the same
> results -- the same network of connected subjects -- from any
> conforming implementation.

I cannot for the life of me see how a TMA can enable this, let alone assure
it. Unless the descriptions of the processes assigned to two properties are
worded exactly in the same way there is no method a machine can use to say
"this property in this applicaiton is exactly the same as that property in
that application". While humans with a good knowledge of the two languages
involved in describing the objects might be able to intuit it they cannot
guarantee it. Are you really able to assure me that "Name of person" is, or
is not, the same as "Nom de femme"? (Michel might give you a clue here!)

> The power to create and interchange TMAs, and the power to create and
> interchange topic maps that are based on them, has at least as much
> value as the power to create and interchange DTDs, and the power to
> create and interchange SGML/XML documents that are based on them.

For the reasons stated above I cannot accept this statement. TMAs are
necessarily subjective rather than objective. They require interpretation by
a human as to the meaning of the definitions. They cannot objectively be
determined by simple character matches, as you can when trying to determine
whether or not SGML/XML markup conforms to a DTD.

Martin Bryan