# both sub- and superscript together?

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If you want to use both subscript and superscript *together*, how do
you make them align horizontally?

E.g., I want to have a^2_i (read in LaTeX), how do you make both '2'
and 'i' align horizontally? The usual way of doing it:

a<sup>2</sup><sub>i</sub>

will make '2' appear before 'i'.

Thanks!

## Re: both sub- and superscript together?

On 7/3/2007 2:40 PM, Ben wrote:

Before anyone asks "Why?", note that having both superscripts and
subscripts on the same variable is not unusual in mathmatics (e.g., in
harmonic analysis).

--

David E. Ross
<http://www.rossde.com/ .

Don't ask "Why is there road rage?"  Instead, ask
"Why NOT Road Rage?" or "Why Is There No Such
Thing as Fast Enough?"
<http://www.rossde.com/roadrage.html

## Re: both sub- and superscript together?

David E. Ross wrote:

...

Maths and chemistry tend to leave the simple (sequential) text
formatting capabilities. I also vaguely remember 6 pre/post/above/below
sub/superscripts, developed for an international standards project...

If you can't find an appropriate representation in Unicode, you better
may use a graphical representation, or a specialized display object.

DoDi

## Re: both sub- and superscript together?

a<sup>2</sup><sub style='position: relative; left: -.5em;'>i</sub> ?

--
Richard.

## Re: both sub- and superscript together?

It works - very nice! Thank you,

Ben

## Re: both sub- and superscript together?

Scripsit Ben:

Unfortunately, that's mostly an illusion. Test it using different fonts and
different browsers, and you'll probably see many variants ranging from very
nice to really awful, like the superscript and the subscript overlaid.

When you shift the subscript to the left - which you can do with other
techniques as well (see e.g. http://www.cs.tut.fi/~jkorpela/math/#subsup ),
you need to make a guess or an estimate on how much it needs to be shifted
to reach the same horizontal position as the superscript. The real effect
depends on the font, and using the em unit does not solve all the problems
here.

So you need to be careful, and the results will still vary, though perhaps
tolerably. It is essential to vertical-align for sup and sub, since
otherwise the effects will be far too different on IE and Firefox (which
have rather different defaults for it).

From the HTML perspective, the basic problem is in that sub and sup elements
are defined in a rather presentation-oriented manner rather than
structurally. When you write <sub>i</sub>, you're saying that i is a
subscript but not what it is associated with. In the given case, "i" is a
subscript for "a" whereas "2" is a superscript (exponent) for the expression
consisting of "a" with subscript "i". There is no way to express this
structural relationship in HTML.

Andreas effectively suggested the safe approach of giving up the idea of
imitating the conventional mathematical notation and using parentheses to
indicate the structure. It unambiguously indicates the meaning, though in a
style that differs from normal math texts. Other approaches involve various
risks, so you need to weigh the risks against the desirability of "math
style" rendering.

--
Jukka K. Korpela ("Yucca")
http://www.cs.tut.fi/~jkorpela/

## Re: both sub- and superscript together?

If you add a span:

a<span class="xscript"><sup>200</sup><sub>i</sub></span>

you can use:

span.xscript {
position: relative;
}
span.xscript sub {
position: absolute;
left: 0.1em;
bottom: -1ex;
}

You might find the small left value is not to your taste.  Of course,
all hell breaks loose if the subscript is longer than the superscript.

I feel sure there are better solutions -- I just can think of any
right now.

--
Ben.

## Re: both sub- and superscript together?

On Tue, 3 Jul 2007, Ben wrote:

Use parentheses:

(a<sub>i</sub>)<sup>2</sup>

http://www.unics.uni-hannover.de/nhtcapri/mathematics.html
http://www.cs.tut.fi/~jkorpela/math /

--
In memoriam Alan J. Flavell
http://groups.google.com/groups/search?q=author:Alan.J.Flavell

## Re: both sub- and superscript together?

Depending on the audience I'd consider rendering LaTeX into an img and
add an alt attribute containing the LaTeX code, at least if you start
using more complicated formulae. A better alternative, if it was more
widely supported already, would be to use MathML
(http://en.wikipedia.org/wiki/MathML ).

Cheers,

Thomas Luzat