# How can I use shorter minus signs in math subscripts?

How can I automatically replace minus signs in subscripts $x_{y-z}$ with text mode minus signs $x_{y\text{-}z}$ without having to type the longer form every time?

• Minus within $x_{y-z}$ is a minus, indeed. On the other hand, "minus" within $x_{y\text{-}z}$ is not a "text mode minus sign" but a regular "dash". Not sure how do you reason the request for such aesthetic intervention, and why do you want to intervene? Which font do you use, can you provide MWE? Oct 19 '19 at 23:00
• The motivation is to save space in equations with many such subscripts. While the normal minus clearly looks better than a dash in general, in subscripts it seems longer than necessary to me. Is such a global replacement possible in LaTeX? Oct 19 '19 at 23:07
• it would be possible but a hyphen isn't really suitable as a minus. The subscript is already using as a smaller font and less space are you sure you want a shorter - as well? Oct 19 '19 at 23:20
• @DavidCarlisle I would like try different options for replacing the minus sign if there is a general way of replacing it in subscripts. Oct 20 '19 at 18:48
• Minus must have the same shape as plus without the vertical line. You cannot use another shape because this corrupts the rythm of such formulae as a+b-c. And what you call "text mode minus" is not minus at all. This is your mistake and missundertanding of typographical principles. Apr 10 '20 at 19:49

I had the same question. Here is what I found:

• There are better ways, to make small minuses, see e.g. this question: Making a shorter minus

• For choosing different symbols depending on the mathstyle you are using \mathchoice comes in handy.

• I do not know yet how to put it over "-" (as far as I can tell using "-" calls your minus-symbol directly)

Here is what I use:

\documentclass{article}
\usepackage{amsmath}
\usepackage{amssymb} %for the \shortminus
\usepackage{graphicx} % for the \scalebox
\DeclareMathSymbol{\shortminus}{\mathbin}{AMSa}{"39}
\newcommand{\medminus}{\scalebox{0.6}[0.7]{$$-$$}}
\newcommand{\minus}{\mathchoice{-}{-}{\medminus}{\shortminus}}

\begin{document}

$a - a _{ a - a _{ a - a } }$
$a \minus a _{ a \minus a _{ a \minus a } }$

\end{document}