Re: mover vs latin chars with diacriticals

Much of the concern in this discussion related to mover versus combining
characters seems to me to be missing the point.  On one hand there is a
concern for  uniqueness of representation and  presumably ease of searching
and on another concern about the quality of the resulting presentation.

I am hearing an argument  to throw out presentation MathML because it fails
an implicit requirement that "a particular mathematical concept be uniquely
represented" and to use a simple character based representation because it
is closer to a unique representation and so easier to search for.

1.  This argument ignores the fact that notations get re-used for different
concepts in mathematics.   To search reliably for a concept, at very least
you need the kind of information contained in the expression

<csymbol definitionURL="..."> ... put your favourite presentation here
</csymbol>

The definition is explicit.  The presentation is along for the ride.

(Think in terms of a test document which discusses the many different uses
of a notation and displays them  in different colors.  However you choose to
represent this, you still need all the information including 1) a reference
to the different definitions and the proper tokenization of each.  Then it
is easy search reliably.  It is also easy to map systematically to your
presentation of choice. )

2.  It is unreasonable to  expect that a single concept to be "presented"
uniformly by all authors or applications (even as a multi-character string)
unless perhaps the presentation is generated by the same author/system on
the same day or is machine generated by the same software.  Even then, other
cultures may deliberately choose a different presentation.

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Bottom line.  If you really want to search for a mathematical concept -
don't compare printer driver instructions --- search where the information
your looking for still exists.  Anything less only a heuristic.

Note that for a character based system, since there is no markup available
to annotate the individual characters, the only real alternative is writing
down your assumptions about the meanings of characters in a separate
document (what else can you do without markup?) and then searching for those
characters.  But this model cannot even handle the simple test case outlined
above.

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Aside:  The discussion about the relative merits of the display of  mover
versus combining characters should be a completely separate discussion about
quality of layout and not confused with the uniqueness of representation or
criticized on that basis.