Index with accented letters

Question

I'm trying to typeset the following

$Q_å=l_å \cdot m$

But LaTeX won't typeset these special or accented letters in my document! Is there a simple way to achieve this?

Answer 1

Names for accents change in math mode, so you should use \mathring a as follows:

\documentclass{article}

\begin{document}

$Q_{\mathring a}=l_{\mathring a} \cdot m$

\end{document}

See the comprehensive list of symbols Table 164 for the other accent commands. Changing input encoding usually does not help for this situation.

ADDITION If your text italics and math italics agree, which is the case by default but may well change if a font package is loaded, then you can implement @daelif's suggestion as follows:

\documentclass{article}

\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage{mathtools}

\begin{document}

$Q_{\textnormal{\itshape å}}=l_{\textnormal{\itshape å}} \cdot m$

\end{document}

I have used \textnormal to negate any formatting from the surrounding text, inputenc to enable input of å directly, fontenc to ensure a font with a good glyph, and mathtools to ensure the size of the subscript is appropriate.

Answer 2

If you're planning on using these accents in math-mode you should use the \accents package. For this specific example, you would use:

$Q_{\accentset{\circ}{a}}=l_{\accentset{\circ}{a}} \cdot m$

which would output:

The accents package is very useful and is well documented (see: CTAN - Accents Package)

Answer 3

You can use this:

\documentclass[varwidth]{standalone}
\usepackage{amsmath}
\begin{document}
    \begin{equation*}
        Q_å=l_å \cdot m
    \end{equation*}
    \begin{equation*}
        Q_{\mathring{a}}=l_{\mathring{a}} \cdot m
    \end{equation*}
\end{document}

Result: