210

I am trying to put two subscripts at the left and right of a character. For example, something like: _{t} p_{x} where p is in the middle. How do you do this?

percusse
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NebulousReveal
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11 Answers11

188

There are many tools for scripts:

  • For general math scripts before something, use \prescript provided by mathtools, for better alignment:

    $ \prescript{14}{2}{\mathbf{C}} $

  • Alternatively, in order to have the left superscript indented to fit better with the shape of the symbol, use \leftindex from the leftindex package:

    $ \leftindex^a_b {f}$
    $ \leftindex[I]^a_b {L} $

  • For large operators, use \sideset from amsmath:

    $ \sideset{_a^b}{'}{\sum} A_n $

  • For tensors, use tensor package:

    $ M\indices{^a_b^{cd}_e} $
    $ \tensor[^a_b^c_d]{M}{^a_b^c_d} $

  • For chemical equations, use mhchem package:

    \ce{^{227}_{90}Th+}

Please complete this list as you can.

The visual result: enter image description here

Source code:

\documentclass{minimal}

\usepackage{mathtools,leftindex,tensor,mhchem}

\begin{document}

\verb!mathtools!: $ \prescript{14}{2}{\mathbf{C}} $

\medskip

\verb!leftindex!: $ \leftindex^a_b {f}$, $\leftindex[I]^a_b {L} $

\medskip

\verb!amsmath!: $ \displaystyle \sideset{_a^b}{'}{\sum} A_n $

\medskip

\verb!tensor!: $ \tensor[^a_b^c_d]{M}{^a_b^c_d} $, $ M\indices{^a_b^{cd}_e} $

\medskip

\verb!mhchem!: \ce{^{227}_{90}Th+}

\end{document}

Gaussler
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Leo Liu
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    +1: I think that this is a great answer because it acknowledges the semantic element of LaTeX environments. Using tensor for, say, denoting an isotope is ontologically dodgy and its visual suitability is contingent on some hypothetical divergence of notation not occurring down the line. – Richard Terrett Feb 21 '11 at 04:53
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    I tried most of these and found the \tensor solution the best one. – Physics_maths Apr 29 '14 at 12:20
  • Are there any options besides mhchem that don't require math mode? I'd like to typeset a downarrow before a letter in a phonetic transcription. – Sjiveru Jul 19 '18 at 23:37
  • @RichardTerrett Worth mentioning that the difference is not just of semantic adherence: \sideset will only work with math operators, not with any item. – Pietro Battiston Dec 11 '19 at 20:15
  • Is there anything wrong (kerning?) with this simple approach? https://tex.stackexchange.com/a/317359/52160 – Pietro Battiston Dec 12 '19 at 07:39
86

Are you doing this in math mode?

${}_{t}p_{x}$

should work.

Alan Munn
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32

The best solution I have seen so far was:

${}_{2}x_{1}$

pic1

For the more general case of left and right superscript and subscript, one writes:

${}^{1}_{2}x^{3}_{4}$

pic2

Jonathan H
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23

The tensor package will do exactly what you require, and more. For your particular case, you need only type

\tensor[_t]{p}{_x}

Regards

Alan Munn
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Frédéric
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22

You could use the leftidx package which is capable of producing left and right subscripts and superscripts.

In contrast to using simply consecutive subscripts or superscripts such as in $_{t}p_{x}$ it takes care of adjusting indices to the argument using \vphantom. From its source:

\newcommand\leftidx[3]{%
  {\vphantom{#2}}#1#2#3%
}
Stefan Kottwitz
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17

The amsmath package has a \sideset command which lets you put indices at all four corners of a symbol (even if this symbol itself has limits above/below):

\[  \sideset{_t}{_x}p  = \sideset{^*_*}{^*_*}\prod_*^*  \]

\sideset is intended to be used with large operator symbols such as \sum and \prod. The amsmath documentation says: this command is not designed to be applied to anything other than sum-class symbols. (Thanks to Stefan Kottwitz for this additional remark.) For other symbols, have a look at the other answers here.

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    Good addition! Just a remark: \sideset is intended to be used with large operator symbols such as \sum and \prod. The amsmath documentation says: this command is not designed to be applied to anything other than sum-class symbols. – Stefan Kottwitz Feb 20 '11 at 02:55
  • @Stefan: Ah, thanks ... I knew I should have looked it up before writing this. – So, don't use this with simple letter-symbols, use the other solutions given here. – Paŭlo Ebermann Feb 20 '11 at 03:03
11

A simple method I apply - which does away with the need for extra packages - is the following:

~^o\!G_{Al}^i

Which produces the following: enter image description here

Henrik L
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    Welcome to TeX.SX! You can have a look at our starter guide to familiarize yourself further with our format. I think this solution is not ideal, because it will cause, at best, inconsistent spacing, or, at worst, a bad line break. – Paul Gessler Oct 25 '14 at 13:56
6

I had the same problem with the subscript and superscript, sooo I made a package to make my life easier and to other. It's a common problem with actuarial symbol, and it help align the sub and superscript. Plus, I’ve add some shortcut to save time.

The project page and the CTAN.

All you need is the actuarialsymbol package.

At the beginning of the code you have to write

\usepackage{actuarialsymbol}

For the sub/superscript

\actsymb['subscripLeft']['superscriptL']{<middle>}{'subscriptR'}{'superscriptR'}

Example of output:

enter image description here

Example of shortcut for actuarial symbol : enter image description here

6

I am dissatisfied with the existing options, including \prescript from mathtools, since they do not even make an attempt at fixing the spacing between the symbol and the left superscript. Therefore, based on egreg’s excellent answer here, I recently added the package leftindex to CTAN. It provides the command

\leftindex^{<left superscript>}_{<left subscript>} {<symbol>}

This measures the negative indentation of the right subscript and indents the left superscript by the same value. This works well for most symbols, with a few exceptions, such as A and L (and P and \Gamma in some fonts other than Computer Modern). Therefore, \leftindex takes a couple of optional arguments. The only one we shall need right now is

\leftindex[<slanting phantom>]^{<left superscript>}
    _{<left subscript>} {<symbol>}

If the command receives a <slanting phantom>, it will use this symbol instead of <symbol> to calculate the indentation of the left superscript.

\documentclass{article}

\usepackage{leftindex}

\begin{document}

Good results: $ \leftindex^a_b {f}, \leftindex^* {M}, \leftindex_q^p {H}, \displaystyle \leftindex_{-\infty}^{\infty} {\int} f(x), dx $

Bad results: $ \leftindex^* {A}, \leftindex^a_b {L} $

With slanting correction: $ \leftindex[T]^* {A}, \leftindex[I]^a_b {L} $

\end{document}

enter image description here


If you grow tired of having to write slanting phantoms manually, you can have a look at my other package, SemanTeX, which provides semantic, keyval-based mathematics where notation can be controlled centrally from the preamble. Its left index support is based on leftindex, but slanting phantoms can now be chosen once and for all from the preamble:

\documentclass{article}

\usepackage{semantex}

\NewVariableClass\MyVar[output=\MyVar]

% No slanting phantom needed:

\NewObject\MyVar\vf{f}

\NewObject\MyVar\vM{M}

\NewObject\MyVar\vH{H}

% Slanting phantom needed:

\NewObject\MyVar\vL{L}[slanting phantom=I]

\NewObject\MyVar\vGamma{\Gamma}[slanting phantom=]

% Slanting phantom and a !! to the % right of the superscript needed:

\NewObject\MyVar\vA{A}[ slanting phantom=I, post upper left=!!, ]

\begin{document}

$ \vf[upper left=a,lower left=b] $, $ \vM[upper left=*] $, $ \vH[upper left=p,lower left=q] $,

$ \vA[upper left=*] $, $ \vL[upper left=a,lower left=b] $

\end{document}

enter image description here

Gaussler
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1

A solution I adopt, whenever I'm working in environments where extra packages are unavailable, is to manually adjust the index position by adding spaces...

For example

{}_{a+b}^c Z

would result in

enter image description here

So, you could do

{}_{a+b}^{\quad c} Z

which gives

enter image description here

But you have to adjust them "case by case" till you find it satisfactory, for example

{}_{ab+\prod x_i}^{\quad\quad\ c} Z

enter image description here

Definitely, punk-LaTex, not ideal and not recommended, but sometimes useful when no better solution is available...

-1

I made one little improvement on Henrik L's answer: I replace the ~ by {}

This removed the extra space given by ~

For my usage, this was important as I improved

$\Sigma _{~^{\wt M} \!  M^{(m)} }^{0,+}$

which appears as

enter image description here

to

$\Sigma _{{}^{\wt M} \!  M^{(m)} }^{0,+}$

which appears as

enter image description here (ok, it's a complicated expression, but it's necessary, and this version makes it prettier!).

cabohah
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Albert
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    Welcome to TeX.SX! Note that MathJaX/MathML is not supported on TeX.SX, so you may want to change $$ $$ into a screenshot :-) – Teddy van Jerry Feb 01 '23 at 17:29
  • The question is about placing subscripts on the left and right of the main character, so this doesn't really provide an answer. – Sandy G Feb 01 '23 at 19:48