# What is this symbol called?

I have just found the following symbol in the book, Multidimensional Real Analysis I: Differentiation by "J.J. Duistermaat and J.A.C. Kolk. The meaning of the symbol is "a map from a subset of the domain to the range". I would like to know the latex code of the symbol.

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What does \kern-1.7pt do? –  Jayesh Badwaik Oct 5 '13 at 9:04
It reduces the kerning of 1.7 points. –  karlkoeller Oct 5 '13 at 9:07
For reference, kerning is a word that refers to the amount of space between glyphs in a line; for example, AVAST requires different kerning between A/V combinations than it does for S/T. –  Sean Allred Oct 5 '13 at 15:02

I didn't find this symbol neither with Detexify nor in "The Comprehensive LaTeX Symbol List".

But it can be obtained with \supset\kern-1.7pt\rightarrow

MWE

\documentclass{article}

\begin{document}
$\supset\kern-1.7pt\rightarrow$
\end{document}


Result

If you want you can define a new command, let's say \supsetarrow, to simplify using it:

\newcommand{\supsetarrow}{\supset\kern-1.7pt\rightarrow}


## Edit from egreg's suggestion

Probably using

\newcommand{\supsetarrow}{\supset\mathrel{\mkern-3.1mu}\rightarrow}


gives better results in sub/superscripts, although not in second level ones.

Choose the one that better fits your needs.

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Using \mathrel{\mkern-3.1mu} instead of \kern-1.7pt makes the symbol print properly also if used in subscripts and independent of the main font size. Of course, different math fonts (say mathpazo, fourier or kpfonts) may require adjusting the length of the back up spacing. –  egreg Oct 5 '13 at 10:01
@egreg I've tried both and my solution seems to print better subsubscripts. Please let me know if I'm wrong. –  karlkoeller Oct 5 '13 at 10:06
I get wrong results with your definition, but good ones with \newcommand{\supsetarrow}{\supset\mathrel{\mkern-3.1mu}\rightarrow} Try it at \huge size with X \supsetarrow Y_{A\supsetarrow B} –  egreg Oct 5 '13 at 10:10
I get better results with egreg's method on okular in subscripts. Otherwise, both work fine. Thanks a lot to both. –  Jayesh Badwaik Oct 5 '13 at 10:32
Right; unfortunately at scriptscript size the amount of backing up is insufficient. Unfortunately it seems that the fix should be dependent on the main font size because the result is good at larger sizes. However, using the symbol at second level subscripts or superscripts seems not so important; just remember that it could be not working in those places. –  egreg Oct 5 '13 at 10:34