From: William Overington (WOverington@ngo.globalnet.co.uk)
Date: Fri Apr 04 2003 - 04:05:39 EST
Stefan Persson wrote as follows.
quote
Well, let's say that I make a plain text document and include a
mathematical formula or funtion such as "cos x", it would still be legal
to use an italic "x" from the mathematical block, wouldn't it? This is
what those characters are intended for, right?
end quote
In the days of letterpress printing, something such as
y = cos x
would have been set with the cos in roman type, probably from an ordinary
serifed font, as might be used for ordinary book printing, and the y and the
x in the italic version of the same typeface. I remember that the typeface
Modern Roman, a serifed face with an upward hook on the end of a capital R
character and a very open lowercase e character, was often used, though not
exclusively.
How should that be set in Unicode plain text? Is it to use the letters for
cos from the range U+0020 to U+007E and then use U+1D466 for the y and
U+1D465 for the x?
I note that U+1D465 MATHEMATICAL ITALIC SMALL X in the code chart has the
following text accompanying the definition, following a symbol which looks
like a wavy equals sign with the word font within angled brackets which I
will not place in this email in case it upsets any email systems, so I will
herein use parentheses.
(font) 0078 x latin small letter x
Yet there would seem to be missing the concept that the character is an
italic of a serifed font.
When trying the MathText program I tried, as I mentioned before, to try to
get MathText to produce Greek characters. This was mainly out of curiosity,
having been studying, as part of the process of studying MathText, the
U1D400.pdf code chart document rather than any immediate need, though with
the thought that such a facility might be useful sometime and that, should
such a situation arise, I could perhaps use MathText to generate the codes.
Yet which Greek characters would I wish to use? Subsequent study of the
U1D400.pdf document raises an interesting matter. I would probably want to
use some of those in the range U+1D6FC MATHEMATICAL ITALIC SMALL ALPHA
through to U+1D71B MATHEMATICAL ITALIC PI SYMBOL. However, whereas I might
well want to use U+1D6FC, the U+1D71B is a symbol which I have not seen
before and indeed wonder what it is, bearing in mind the existence of
U+1D70B MATHEMATICAL ITALIC SMALL PI.
Yet the interesting point which has arisen is this. The most common use of
such italic letters would seem to be, from my own potential usage, would be
for angles theta, phi and psi for expressing rotation angles.
U+1D713 MATHEMATICAL ITALIC SMALL PSI for psi.
U+1D703 MATHEMATICAL ITALIC SMALL THETA for theta rather than using U+1D717
MATHEMATICAL ITALIC THETA SYMBOL.
U+1D719 MATHEMATICAL ITALIC PHI SYMBOL for phi, rather than using U+1D711
MATHEMATICAL ITALIC SMALL PHI.
I seem to remember a discussion in this group about the two versions of phi
in relation to ordinary Greek characters some time ago.
William Overington
4 April 2003
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