3

Using amsmath and extarrows packages, we have many extensible arrows. But these arrows look ugly, since some parts in an arrow are boldfaced.

enter image description here

Are there any better-looking extensible arrows?

Z.H.
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    They are not really bold, just overlapping slightly which affects the anti-aliasing in low resolution. They should print OK. tikz or pstricks or xypick can all draw arrows instead of using repeated character segments, which may suit you better – David Carlisle Oct 07 '13 at 08:52
  • @DavidCarlisle The overlapping makes arrows look ugly when reading document in computer. Why overlapping is necessary in these extensible arrows? I notice that in xypic, long arrows look better than these. – Z.H. Oct 07 '13 at 09:03
  • @DavidCarlisle But how to use an arrow drawn by tikz or xypic as an operater inside a math formula? It seems not easy. – Z.H. Oct 07 '13 at 09:14

1 Answers1

5

This is a substitute for \xrightarrow made with Xy-pic

\documentclass{article}
\usepackage[all,cmtip]{xy}

\newlength{\xywd}
\newcommand{\xyrightarrow}[2][]{%
  \sbox{0}{$\scriptstyle#1$}%
  \xywd=\wd0
  \sbox{0}{$\scriptstyle#2$}%
  \ifdim\wd0>\xywd \xywd=\wd0 \fi
  \xymatrix@C\dimexpr\xywd+1em\relax{{}\ar[r]^{#2}_{#1}&{}}%
}


\begin{document}
[
X \xyrightarrow[r_1-r_2]{r_2-r_1} Y
]
[
X \xyrightarrow[r_1-r_2+r_3]{r_2-r_1} Y
]
[
X \xyrightarrow{r_2-r_1} Y
]
\end{document}

enter image description here

egreg
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