Re: Superscript asterisk

From: Asmus Freytag (asmusf@ix.netcom.com)
Date: Thu Jul 01 1999 - 14:41:05 EDT


Jonathan,

the group working on the math proposal has gone a different direction after
long and fruitful discussions in the Unicode Technical Committee. For math,
these 'presentation' suggestions are in fact priamry _semantic_
differences. FRAKTUR (not 'black letter') H denotes a Hilbert space, SCRIPT
H denotes a Hamiltonian etc. In order to reliably do math in plaintext one
would have to assume that the presentation differences are reliably
communicated along with the text, whether the text is sent by mailers,
temporarily hosted in HTML, then exported again etc.

After considering this, and the implementation complexity cost for all
installations, it was decided that stateful controls (along the lines you
suggest) are not the best way to go. In particular they tend to interact
very badly with markup languages. We thought briefly about 'combining style
marks' and rejected that idea as well.

We finally settled on adding a set of "Math Styled Alphabets" to the
surrogate space (Plane 1 in 10646), or about 1000 characters from the base
Latin and Greek alphabets, plus digits, in only those style / case
combinations as are actually used in the mathematical literature. We are in
active collaboration with a consortium of mathematicsl publishers,
including the American Mathematical Society (AMS), so we are pretty
confident that the set we have picked is indeed the set of Letterforms used
by mathematicians as distinct elements for symbolic notation.

The proposed sets are deliberately _not_ including many letters that would
be needed to use them for styled *text*, since we don't propose that text
styles should be handled in plain text (those are better left to markup and
style sheets). One of the drawbacks of your proposal is that it is open
ended in that regard, i.e. it is a complete style markup (just add font
size ;-).

A./

PS: if you or any one else is wondering about plane 1 (or the 'next 64K
characters): The contents of this area will be empty for the upcoming
Unicode 3.0, but work has started on ISO/IEC 10646-2 (read "part 2") which
will contain characters in planes 1,2 and 14. ETA for part 2 is about 1-2
years. Plane 2 characters will contain a much needed set of ideographs for
Hong Kong, meaning a number of the large vendors are implementing support
for surrogates right now in order to be ready when these characters are
defined. Please be cool and support surrogates at least passively in your
own applications from today.



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