# Left version of \mapsto [duplicate]

Possible Duplicate:
How to look up a math symbol?

I there a version of \mapsto going from right to left (i.e a "\leftmapsto"? Is there an easy way of creating such a symbol?

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## marked as duplicate by Joseph Wright♦Sep 8 '11 at 15:35

If one doesn't exist, you could make one with the graphicx package and \reflectbox{\mapsto} –  Seamus Aug 25 '11 at 12:05
Welcome to TeX-SX! For questions like this, there are some very good resources that are in the question linked in Jake's comment above. To help others find these resources quickly, we'll probably close this question as a duplicate of that one. This is just to ensure that other people find their way to that "canonical question" as easily as possible. –  Loop Space Aug 25 '11 at 12:34

\mapsfrom from the stmaryrd package.

You can look up such symbols using Detexify

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• MnSymbol provides \leftmapsto
• stmaryrd provides \mapsfrom
• with graphicx you can create one: \newcommand\mapsfrom{\mathrel{\reflectbox{\ensuremath{\mapsto}}}}
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Your command \mapsfrom gives the wrong spacing as it is defined. –  Gonzalo Medina Aug 25 '11 at 12:17
That's easily fixed: Just define the command as \newcommand{\mapsfrom}{\mathrel{\reflectbox{\ensuremath{\mapsto}}}}. The \mathrel command tells (La)TeX to treat \mapsfrom as a relational operator. –  Mico Aug 25 '11 at 13:00
Fix'd (I hope). Thanks for pointing that out. –  Seamus Aug 25 '11 at 13:26

The symbols document gives you \mapsfrom from the stmaryrd package or \leftmapsto to from the MnSymbol package:

\documentclass{article}
\usepackage{stmaryrd}
\usepackage{MnSymbol}
\begin{document}

%requires stmaryrd
$a\mapsfrom x$

% requires MnSymbol
$a\leftmapsto x$

\end{document}


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