arrowsmath-mode
Similar to this question, I want to write some text above $\nrightarrow$. This is what I could do:
\documentclass{article}
\usepackage{mathtools}
\usepackage{amssymb}
\begin{document}
$\nrightarrow$
$\nrightarrow^{\text{Hello}}$
\end{document}
As you can see, the text is not properly aligned.
So, I seek help in putting the text right on top.
Additionally, it would be appreciated to faciliate extending the arrow to fit the text.
If you put an accent over a single character, TeX uses information in the font metrics to shift the accent to take some account of the slope of the italic letters. Which is why the first one shifts. If you put an accent over a more complicated math list then it's just centered over the list.
As percusse mentions in his comment, you can use a node and a decorated arrow; something like this:
\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations.pathmorphing,shapes}
\newcounter{sarrow}
\newcommand\xrsquigarrow[1]{%
\stepcounter{sarrow}%
\begin{tikzpicture}[decoration=snake]
\node (\thesarrow) {\strut#1};
\draw[->,decorate] (\thesarrow.south west) -- (\thesarrow.south east);
\end{tikzpicture}%
}
\begin{document}
\xrsquigarrow{text}\quad\xrsquigarrow{longer text}
\end{document}
The following code contains a new version of \xrsquigarrow using the zigzag decoration and \mathrel to be used in math-mode; it shows a comparison between \xrightarrow, \rightsquigarrow and \xrsquigarrow (some fine-tuning is still required, but I leave that to you):
\documentclass{article}
\usepackage{amsmath,amssymb}
\usepackage{tikz}
\usetikzlibrary{calc,decorations.pathmorphing,shapes}
\newcounter{sarrow}
\newcommand\xrsquigarrow[1]{%
\stepcounter{sarrow}%
\mathrel{\begin{tikzpicture}[baseline= {( $ (current bounding box.south) + (0,-0.5ex) $ )}]
\node[inner sep=.5ex] (\thesarrow) {$\scriptstyle #1$};
\path[draw,<-,decorate,
decoration={zigzag,amplitude=0.7pt,segment length=1.2mm,pre=lineto,pre length=4pt}]
(\thesarrow.south east) -- (\thesarrow.south west);
\end{tikzpicture}}%
}
\begin{document}
\[
A\xrightarrow{f} B\quad A\rightsquigarrow B\quad A\xrsquigarrow{f}B\quad A\xrsquigarrow{(f\circ g)\circ h}B
\]
\end{document}
This definition does not cover the case in which the arrow is to be used in super/sub-scripts.
Best Answer
Maybe something like
where a negation symbol is superimposed to the standard
\xrightarrow. The negation symbol is a fattened bar which is rotated.