Hyphen separating symbols, without intervening spaces

Question

What's the easiest/least ugly way to avoid the spaces around the hyphen in the following macro?

\documentclass{article}

\newcommand{\nuSwap}{\nu-\textsf{swap}}

\begin{document}
I get $\nuSwap$, but I want $\nu$-\textsf{swap}.
\end{document}

I would like a macro I can use easily when I'm already in math-mode.

Answer 1

In math mode (as in your $\nuSwap$) the - becomes a minus sign and is thus longer and has spaces around it. Simply preventing the - from being treated as maths as you do with the word swap gives what you want, e.g. by redefining:

\newcommand{\nuSwap}{\nu\textsf{-swap}}

in which case:

\documentclass{article}

\newcommand*{\nuSwap}{\ensuremath{\nu\textsf{-swap}}}

\begin{document}
You want \nuSwap, here's \(\nu\)-\textsf{swap}.

And \nuSwap ping also works in maths mode:
\[\nuSwap\]
\end{document}

gives:

Answer 2

As already mentioned, the hyphen is interpreted as a minus in math mode. To correct the issue you could define a macro \mhyphen that stands for the hyphen in math mode:

\mathchardef\mhyphen="2D
\newcommand{\nuSwap}{\nu\mhyphen\textsf{swap}}

this can of course be combined with \ensuremath to get a macro that works in both modes.

I also recommend using \texorpdfstring (from hyperref) if you intend to use it in headers and produce a pdf:

\documentclass{article}
\usepackage{hyperref}

\mathchardef\mhyphen="2D
\newcommand{\nuSwap}{\texorpdfstring{\ensuremath{\nu\mhyphen\textsf{swap}}}{nu-swap}}

\begin{document}
\section{Definition of \nuSwap}

Here we define \nuSwap:

\[
    \nuSwap = \dots
\]
\end{document}

if you inspect the generated PDF you'll find "nu-swap" is used in the index.

Answer 3

The hyphen should be in sans serif style. However, using \textsf{-swap} might render it in italics, if in a context where italics is used (theorem statements, for instance).

Safe solution: use the same trick as amsmath for using a hyphen in the argument to \operatorname instead of a minus sign.

\documentclass{article}
\usepackage{amsmath}

\makeatletter
\newcommand\nuSwap{\nu\mathsf{\newmcodes@-swap}}
\makeatother

\begin{document}

I want $\nuSwap$

It also respects bold math {\boldmath$\nuSwap$}

\end{document}