Equivalent of \mathup for upright text in math mode?

Question

To insert text in mathmode, there are a couple of commands:

• \mathrm for Roman script,
• \mathbf for bold weight,
• \mathit for italic shape,
• \mathsf for the sans serif variant,

and so on. Now, sometimes I would like to have some math entities typeset upright (see for example How to best typeset "special" constants (complex unit i, Euler's number e,...)?). I understand that \mathrm sets the text in Roman and upright, but in some cases I do not want serifs (e.g., in presentations). The command \mathup does not seem to exist.

What is recommended way to set upright text in math mode?

Answer 1

I guess what you are seeing is the following when you use \mathrm with a serif font:

\documentclass{beamer}

\usepackage{amsmath}

\begin{document}

\begin{frame}
  \( x y \mathrm{x} \text{\textup{x}}\)
\end{frame}

\end{document}

There are two ways to fix this: one fairly drastic option is to put

\renewcommand{\rmdefault}{cmss}

but this may feed through to places you are not expecting. An alternative is to replace the two relevant definitions from beamerbasefont.sty by

\AtBeginDocument{%
  \SetMathAlphabet{\mathrm}{normal}{\encodingdefault}{cmss}{\mddefault}{n}
  \SetMathAlphabet{\mathrm}{bold}{\encodingdefault}{cmss}{\bfdefault}{n}}

in your preamble. In the beamer style file {cmss} is {\rmdefault}.

Applied to the above example, either method gives you:

Answer 2

The package unicode-math for XeLaTeX and LuaLaTeX does the job and offers \mathup.

Answer 3

Your question was: in what cases to use sans serif in math.

In Czech traditional typography (and maybe in the middle Europe too) the vectors and matrices are signed by sans serif bold slanted (or upright) variants. This math alphabet was not preloaded by default in plain TeX (and derived formats), so we are seeing serifs bold in such cases in typical TeX documents, unfortunately.

The Unicode math fonts include many math alphabets including bold sans-serif upright and slanted Latin and Greek, so there is no problem. But there is strong tradition in TeX documents to use serif bold although there is no technical limitations when we are using Unicode math fonts today.

Answer 4

If using pandoc with th xelatex-engine to render a PDF \symup was the correct solution for me to have upright units like so \symup{{\mu}m}, for example.

My tex-template is loading unicode-math instead of mathspec despite xelatex is being used. Fortunately I might add, because a not resolved bug in mathspec is preventing it's use together with \siunitx, because it requires \amsmath loaded before and throws this error even if I do so in the template used by pandoc.