# [texhax] shift subscript without superscript

Deimantas Galcius deimi at vtex.lt
Fri Jun 10 13:36:25 CEST 2016

Hi Arno,

You can find about this in TeXbook, Chapter 18 Fine points of mathematics, p. 179.
\fontdimen16, \fontdimen17 controls the position of subscripts; \fontdimen14 controls the superscript position.

regards,

-- deimi

On 06/10/2016 02:09 PM, Arno Trautmann wrote:
> Hi all,
>
> this is a question that bugged me for a long time but I never dared to ask, nor did I find discussions of this so far. Consider the simple document:
>
> \documentclass{minimal}
> \begin{document}
> $a_i a_i^\dagger + b_i b_i^\dagger$
> $a_i^{} a_i^\dagger + b_i^{\strut} b_i^\dagger$
> \end{document}
>
> The first line is the normal input, and operators like this are used frequently in quantum physics. The disturbing point are the subscripts which are shifted
> further down if there is a superscript. I'm aware that this is a nice feature normally, but in this case I would like to see them at the same height.
> In the second line of the example, the expression with the b operators shows the desired result, while the expressions with a operators show the three
> different positions of the subscript.
> It is not very practical to add the ^{\strut} for every occurance – especially if you think of a document a colleague wrote and there are hundreds of these.
> Also, the \strut here causes too much space due to its excess height.
>
> So, finally the question: Is it possible to default the subscript of any expression to be at the lowest position? (And, vice versa for the superscript to be
> at the topmost position?) I'll happily appreciate TeX hackery, package solutions, or Lua code … whatever helps :)
>
> Best,
> Arno
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