[Tex/LaTex] How to properly typeset E_{\mathrm{k}} in beamer

beamerfonts

Scientific typography makes an important distinction between italic type and roman (upright) type (exemplary source).

The symbol for kinetisch energy is E_k with E printed in italic type, k printed in roman type.

Normally, I would write that as E_{\mathrm{k}}.

However, that does not work with beamer. The package changes normal math to a sans-serif font, but leaves \mathrm a serif-font. The subscript k will be typeset in a serif-font, but it should simply match the default math font, just being upright.

So how do I get the intended behavior in beamer?

\documentclass{beamer}
\begin{document}
\begin{frame}
  $E_{\mathrm{k}}$
\end{frame}
\end{document}

(Other packages that switch to sans-serif math fonts also redefine mathrm to be sans-serif and, of course, upright, e.g. cmbright, sfmath and arevmath.)

Best Answer

By adding \usefonttheme[onlymath]{serif}, we find the serif font in mathematical formulas.

\documentclass{beamer}
\usefonttheme[onlymath]{serif}
\begin{document}
\begin{frame}
  $E_\mathrm{k}$
\end{frame}
\end{document}

Output:

Related Solutions

[Tex/LaTex] Shouldn’t Beamer redefine \mathrm

As Paul Gessler suggested, you can use \text{} instead of \mathrm{} when you want upright rather than specifically roman text. Since you are using beamer, you don't even need to load any additional packages:

\documentclass{beamer}
\begin{document}
  $abc\text{abc}$
\end{document}

upright sans in maths mode

If you are producing an article version as well, you obviously want TeX to do the right thing in that case, too:

\documentclass{article}
\usepackage{beamerarticle}
\begin{document}
  $abc\text{abc}$
\end{document}

upright roman in maths mode

This works because by default, beamer loads several ams packages. If you are not using beamer, you would need to load them yourself as Paul Gessler mentioned.

[Tex/LaTex] Sans-serif bold math with newtxmath

You should also load newtxtext, for the text fonts. A small correction should be made as well, for \mathsf{\Omega}. Also load bm, which is better than the standard version for \boldsymbol provided by amsmath. You can also use \bm instead of \boldsymbol.

\documentclass{article}

\usepackage{amsmath}
\usepackage{bm}
\usepackage{newtxtext,newtxmath}

\DeclareMathAlphabet{\mathsf}{OT1}{\sfdefault}{m}{n}
\SetMathAlphabet{\mathsf}{bold}{OT1}{\sfdefault}{b}{n}


\begin{document}

Sans serif, no bold: $\mathsf{A}, \mathsf{\Omega}$

Sans serif, bold: $\boldsymbol{\mathsf{A}}, \boldsymbol{\mathsf{\Omega}}$

\end{document}

Best Answer

Related Solutions

[Tex/LaTex] Shouldn’t Beamer redefine \mathrm

[Tex/LaTex] Sans-serif bold math with newtxmath

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