Left version of \mapsto [duplicate]

Question

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?

Answer 1

\mapsfrom from the stmaryrd package.

You can look up such symbols using Detexify

Answer 2

• MnSymbol provides \leftmapsto
• stmaryrd provides \mapsfrom
• with graphicx you can create one: \newcommand\mapsfrom{\mathrel{\reflectbox{\ensuremath{\mapsto}}}}

Answer 3

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}