Notes on Notes on Marston Presentation

[david_marston@us.ibm.com]

Some wording details in Dennis Hamilton's
notes that should be corrected:

"Example of
different levels for MathML: formula presentation versus interpretation
of the formula"

Actually, "level" is a different
Dimension of Variability, which became clear later in the presentation.
The two uses of MathML described above illustrate how one spec can specify
behavior of two classes of product. And small vs. large display is more
likely to represent two profiles rather than two classes of product. Rendering
audibly vs. visibly could go either way: if you focus on read-only rendering,
you are identifying two profiles that perform the same functionality (make
a document comprehendable to humans); or you could call them different
classes of product if the conformance expectations are considered very
different.

Levels are supposed to be about functionality.
For example, a Level N implementation would be required to have the features
defined in all levels up to N-1, plus additional features that belong to
Level N (and higher levels).
.................David Marston
IBM Research