left superscript
Rita Bijlsma
How can I make a superscript at the left corner of a
math letter, that is an italic letter, without having to much
space between the superscript and the following letter it
should belong to?
Many thanks for any help!
Rita
--
.-. || Drs. Rita Bijlsma tel: +31-15-2787109
/ \|| IRI dept of Radiation Physics fax: +31-15-2786422
| ||| Delft University of Technology email: ri...@iri.tudelft.nl
| |||_The Netherlands ______________ http://www.iri.tudelft.nl/~rita
Frank Ecke
> How can I make a superscript at the left corner of a
> math letter, that is an italic letter, without having to much
> space between the superscript and the following letter it
> should belong to?
In plain TeX, say
${}^b\mkern -3mu I$
and adjust the \mkern to taste.
Hope this helps.
Frank
--
Frank Ecke <fra...@minet.uni-jena.de>
In a world without walls and fences, who needs windows and gates?
Marc Joosen
>
> Hi,
>
> How can I make a superscript at the left corner of a
> math letter, that is an italic letter, without having to much
> space between the superscript and the following letter it
> should belong to?
\sideset is the way to do this (see the LaTeX Companion, p. 226),
but if you want to, no one is going to stop you from using \kern :)
--
marcj
Thomas Ruedas
least the amsmath doc suggests it, although it admittedly would be a
rather senseless restriction.
(too lazy to try it out)
--
--------------------------------------------
Thomas Ruedas
Institute of Meteorology and Geophysics,
J.W. Goethe University Frankfurt/Main
Feldbergstrasse 47 D-60323 Frankfurt/Main, Germany
Phone:+49-(0)69-798-24949 Fax:+49-(0)69-798-23280
e-mail: rue...@geophysik.uni-frankfurt.de
http://www.geophysik.uni-frankfurt.de/~ruedas/
--------------------------------------------
Marc Joosen
>
> > \sideset is the way to do this (see the LaTeX Companion, p. 226),
> Isn't sideset only working with certain operators as \prod or \sum? At
> least the amsmath doc suggests it, although it admittedly would be a
> rather senseless restriction.
> (too lazy to try it out)
I have successfully used \sideset with \log to get the base number
right (that is, to the left :) It is true that the LaTeX Companion only
mentions \sideset in conjunction with \prod and \sum, but no word of
restrictions...
--
marcj
Michael J Downes
> Isn't sideset only working with certain operators as \prod or \sum? At
> least the amsmath doc suggests it, although it admittedly would be a
> rather senseless restriction.
No, not senseless. There are technical difficulties. In order to add a
left-superscript to an arbitrary math symbol, it would be necessary to
analyze the symbol to determine its "math class" (binary operator,
relation, delimiter, ordinary, large operator, etc), in order to apply
the correct math spacing to the composite math object produced by the
superscripting operation. (A math atom with left sub/superscripts is
not a primitive atom type supported by TeX, so you have to build it by
putting two atoms together in a composite object.)
Furthermore, any math symbol that does not have a more or less
perpendicular alignment of its left-top and left-bottom corners will
require some horizontal adjustment to get good visual placement of
left-superscript and left-subscript. On the right-hand side of a math
symbol, the information about how much adjustment is needed is
provided as the "italic correction" in the TeX font metric file.
No such information is provided for the left-hand side, so in general
one would have to do any adjustments by hand.
For these two reasons, the \sideset command is specifically targeted
to math symbols of class 1 (mathops like \sum and \prod) and the
composite object that it produces has class 1. That's the way it was
written originally (by Michael Spivak for AMS-TeX, circa 1983), and
the current implementation in the LaTeX amsmath pkg is fundamentally
the same. Fortuitously the two most common mathop symbols, \sum and
\prod, have a perpendicular left profile, or else they too would be
affected by the lack of left-superscript horizontal adjustment info.
Left-hand sub/superscripts can lead to badly written mathematics if
the user is not careful: If you attach a left subscript or a left
superscript to a math symbol and then place another symbol in front of
it, you have to be careful to add extra space to avoid possible
misinterpretation of the left sub/superscript as a right
sub/superscript of the preceding symbol. This is less of a problem if
the base symbol is of class "binary operator" or "relation" that has
extra spacing built in; but for math symbols of class "ord" (that take
no additional spacing on either side) the convention of restricting
sub/superscripts to the right side only is a counter-ambiguity measure
that follows directly and naturally from the linear nature of a stream
of written mathematics.
If you *do* need to put sub/superscripts on the left of something
(let's say, because it is a long-established tradition in your field
:-), the best way is to do it with two atoms and a wrapper, where the
wrapper depends on the class of the base atom:
Here is a left-sup 2 in a cap F. The F leans to the right so a
horizontal adjustment is needed:
\mathord{{}^{2\mkern-4mu}F}
And here is a left-sup * on a plus sign (math class 2, binary operator)
\mathbin{{}^{*\mkern-3mu}\mathord{+}}
And here is a left-sub a and left-sup b on an equals sign (math class
3, relation)
\mathrel{{}_a^b\mkern-2mu\mathord{=}}
In the case of the + sign the \mathord is not strictly necessary since
TeX automatically deduces that a binary operator should be changed to
class mathord if it doesn't have a suitable symbol on both sides.
Michael Downes
tech-s...@ams.org
Thomas Ruedas
command in such a way that it works for different classes of math
symbols, it would have been useful to provide another command to write
left super/subscripts to normal variables; AFAIK - and this discussion
seems to prove it - there is no such command. However, the question of
Rita shows that it would be needed. BTW, I encountered a manner of
writing spherical harmonics with left and right indices some time ago; I
don't know if that's a "long-established tradition" in geophysics, but I
don't think so.
However, thanks for your information and for the examples you gave.