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Re: empty set symbol in MathML

From: Neil Soiffer <NeilS@DesSci.com>
Date: Mon, 5 Apr 2004 11:32:02 -0700
Message-ID: <03de01c41b3c$4a4e9c30$6601a8c0@raindrops>
To: "Robert Miner" <RobertM@dessci.com>, <info@soft4science.com>
Cc: <www-math@w3.org>


----- Original Message ----- 
From: "Robert Miner" <RobertM@dessci.com>
To: <info@soft4science.com>
Cc: <www-math@w3.org>
Sent: Monday, April 05, 2004 7:51 AM
Subject: Re: empty set symbol in MathML


> Hi.
>
> Other experts will correctly me if I'm wrong, but my memory is that
> Unicode doesn't acknowledge these as separate character. Instead, they
> are regarded a "glyph variants" of the same character, and thus they
> do not get separate code points.

I believe that was the reasoning of the Unicode technical committee.  If you
can cite published books or articles that use both symbols/variants in them
for different meanings, this can be submitted to the technical committee as
proof that they aren't variants and the character will be considered for
addition in a future revision of Unicode.  My memory is that we were unable
to come up with such examples.  It would be great if people on this list
could come up with some supporting material.


> This is supported by a quick search of the Unicode 4 character
> database.  Another family of characters that are separate in TeX, and
> for which we requested separate codepoints are the long arrows.  In
> this case also, Unicode rules they were glyph variants.
>

At the last minute, the Unicode folks relented and allowed some long arrows.
See http://www.unicode.org/charts/PDF/U27F0.pdf


Neil Soiffer                     email: neils@dessci.com
Senior Scientist                 phone: 562-433-0685
Design Science, Inc.             http://www.dessci.com
"How Science Communicates"
MathType, WebEQ, MathPlayer, Equation Editor, TeXaide
Received on Monday, 5 April 2004 14:32:35 GMT

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