W3C home > Mailing lists > Public > www-math@w3.org > May 2006

Re: mover vs latin chars with diacriticals

From: Stan Devitt <jsdevitt@stratumtek.com>
Date: Wed, 3 May 2006 00:21:17 +0200
Message-ID: <ce9128ae0605021521s8c9bf87tc7a65789b65b689f@mail.gmail.com>
To: "David Carlisle" <davidc@nag.co.uk>
Cc: neils@dessci.com, www-math@w3.org
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

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.


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


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.
Received on Tuesday, 2 May 2006 22:21:23 UTC

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