Resize verbatim in exponent equation mode

Question

I have this inline equation

$2^{\verb|N|-1}$

that gives this result

The problem is that using \verb|N| leaves N with the same size as in \displaystyle but I want it to be smaller.

How can I do?

Answer 1

Two alternatives with automatically resized N:

\documentclass{article}
\usepackage{amstext}% or package amsmath for \text
\newcommand*{\ttmath}[1]{%
  \texttt{\mdseries\upshape#1}%
}

\begin{document}

  $2^{\verb|N|-1}$ {\small(\verb|\verb|)}

  $2^{\texttt{N}-1}$ {\small(\verb|\texttt| with \verb|amstext|)}

  \textit{Italics $2^{\ttmath{N}-1}$ context} {\small(macro \verb|\ttmath|)}

  $2^{\mathtt{N}-1}$ {\small(\verb|\mathtt|)}

\end{document}

Remarks:

• \texttt here works with automatically resizing in math mode because it internally uses \nfss@text that is redefined in package amstext as \text.

• Macro \ttmath also resets font attributes series and shape to get independent from the current text font setting.

• \mathtt is the most efficient command and uses the configured typewriter font for math. This is often the same as \ttfamily. Some font packages switch both fonts at the same time as lmodern, others do not as beramono. Therefore, it depends on the font setup, whether \mathtt can be used instead of \verb or \texttt.

Answer 2

The LaTeX kernel defines \mathtt and nothing else is necessary. By the way, \verb should not be abused for printing in the typewriter font, usually \texttt is enough, whereas \verb is needed for printing TeX code with special characters.

\documentclass{article}

\begin{document}

$2^{\mathtt{N}-1}$

$2^{\mathtt{N}^{\mathtt{M}}}$

\end{document}

It's probably useful to define your own semantic command, say

\newcommand{\tvar}[1]{\mathtt{#1}}

and use $2^{\tvar{N}}$. This way you're not tied to the particular representation that you can change at any time by just modifying the definition.

It may happen that the choice of a different font set doesn't update \mathtt. The solution is simple and the advantage over other solutions involving \text is that this can be easily adapted to support \boldmath out of the box.

\documentclass{article}
\usepackage[T1]{fontenc} % necessary for beramono
\usepackage{amsmath}

\usepackage{beramono}

% update \mathtt to use the same font as \ttfamily
\DeclareMathAlphabet{\mathtt}{\encodingdefault}{\ttdefault}{m}{n}
% if the monospaced font also supports boldface (b or bx)
\SetMathAlphabet{\mathtt}{\encodingdefault}{\ttdefault}{b}{n}

\newtheorem{theorem}{Theorem}

\begin{document}

$2^{\mathtt{N}-1}$ and \texttt{N}

\begin{theorem}
Something about $2^{\mathtt{N}-1}$
\end{theorem}

\end{document}

---

Side note

Using \texttt is wrong, as exemplified by the following code.

\documentclass{article}
\usepackage{amsmath}

\newcommand{\tvar}[1]{\mathtt{#1}}

\newtheorem{theorem}{Theorem}

\begin{document}

\section*{Right}

$2^{\tvar{N}-1}$

\begin{theorem}
Something about $2^{\tvar{N}-1}$
\end{theorem}

\section*{Wrong}

$2^{\texttt{N}-1}$

\begin{theorem}
Something about $2^{\texttt{N}-1}$
\end{theorem}

\end{document}

Answer 3

A solution using this answer of Werner: https://tex.stackexchange.com/a/120694/120578

\documentclass{article}
\usepackage{verbatim}% http://ctan.org/pkg/verbatimes
\usepackage{pgf}
\makeatletter
\newcommand{\mverbatimfont}{\def\verbatim@font{\ttfamily}}%
\makeatother
\def\verbatimfont#1{\pgfmathsetmacro\bls{1.2*#1}\mverbatimfont\fontsize{#1}{\bls}\selectfont}


\begin{document}
\verbatimfont{6}
$2^{\verb|N|-1}$

\verbatimfont{9}
$\verb|N|^{\verbatimfont{6}\verb|N|-1}$
\end{document}

Output: