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Sometimes some .tex features or standards seem strange at first glance. One actual case for me are subscripts with capital letters (obligatory because the letters on subscripts came from acknowledged scientist names) that seem too big to me. I want to reduce them. Their height should not be beyond 30% of the mother's. See the example bellow:

\begin{equation}
\sigma_{C} = \sigma_P + \frac{\sigma_H^2}{\sigma_P}.
\label{Cowling}
\end{equation}

condutivities

Related posts: etiquette-for-math-subscripts-and-superscripts

subscripts-not-scaled-accordingl

Ps. I am showing a relation for ionospheric condutivities. Hall, Pedersen, Cowling, paralel.

2 Answers 2

5

You could drop the size by one "style", from \scriptstyle down to \scriptscriptstyle:

enter image description here

\documentclass{article}
\usepackage{amsmath}

\newcommand{\Cowling}{{\mathchoice{}{}{\scriptscriptstyle}{}C}}
\newcommand{\Hall}{{\mathchoice{}{}{\scriptscriptstyle}{} H}}
\newcommand{\Pedersen}{{\mathchoice{}{}{\scriptscriptstyle}{} P}}
\begin{document}

\begin{align*}
  \sigma_{C}   &= \sigma_P + \frac{\sigma_H^2}{\sigma_P} \\
  \sigma_{\Cowling} &= \sigma_{\Pedersen}+ \frac{\sigma_{\Hall}^2}{\sigma_{\Pedersen}} \\
  \Cowling_{\Pedersen} &\neq \Hall
\end{align*}

\end{document}

The above defines \Cowling, \Hall and \Pedersen as the "symbols" C, H and P, respectively. Each symbol is scaled down to \scriptscriptstyle - using \mathchoice - when used in a super-/subscript, otherwise they're kept the same.

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  • 2
    I wouldn't recommend this. Using \sigma^{}_{P} will move the subscript a bit down, which is all is needed. Using \scriptscriptstyle unbalances everything.
    – egreg
    Commented Nov 13, 2014 at 23:06
  • A combination of the solution by @Werner and @egreg solution gives me a nice output. For example \Cowling^{}_{\Pedersen} &\neq \Hall Commented Dec 13, 2019 at 13:42
3

I'd simply add an empty superscript in order to move the subscript down.

\documentclass{article}
\usepackage{amsmath}

\makeatletter
\newcommand{\add@empty@sup}{\@ifnextchar^{}{^{}}}

\newcommand{\sC}{\sigma_{\!C}\add@empty@sup}
\newcommand{\sP}{\sigma_{\!P}\add@empty@sup}
\newcommand{\sH}{\sigma_{\!H}\add@empty@sup}

\begin{document}

\begin{equation}
\sC = \sP + \frac{\sH^{2}}{\sP}
\end{equation}
\begin{equation}
\sigma_{C} = \sigma_P + \frac{\sigma_H^2}{\sigma_P}.
\end{equation}

\end{document}

I reported also the original input for comparison. Note that I refined a bit the macros in order to add a small negative space to push the subscript nearer to the sigma.

enter image description here

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