Re: Character for e, 2.71828...

From: Doug Ewell (dewell@adelphia.net)
Date: Sun Apr 07 2002 - 13:36:10 EDT


Elliotte Rusty Harold <elharo@metalab.unc.edu> wrote:

> Does anybody happen to know the appropriate Unicode character for
> the base of the natural logarithms, e? Paging through the Unicode
> spec I found a number of candidates in various blocks including
> 0065, 212E, and 212F but none of which identified themselves as
> this number in particular.

You should use U+0065 LATIN SMALL LETTER E. The concept of e is usually
represented with an ordinary e, or at most an italicized e (in which
case U+1D452 MATHEMATICAL ITALIC SMALL E might be appropriate), rather
than a distinct glyph which would call for the creation of a new
character.

The creation of a separate symbol to represent a concept like this is
generally discouraged. Despite the presence of U+212B ANGSTROM SIGN,
for example, the use of U+00C5 LATIN CAPITAL LETTER A WITH RING ABOVE to
express a wavelength is preferred.

You should probably not use U+212F, and *definitely* not U+212E, to
represent the math constant e, because there are specific annotations
for the use of these characters that should not be overloaded. (I was
politely reminded of this when I suggested an existing character to be
used for Robert Palais' proposed "2 pi" symbol.)

-Doug Ewell
 Fullerton, California



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