# Measure restriction sign

I need to use a notation for the restriction of a measure to a set. It is similar to \mu \llcorner A, but I want the symbol defined by \llcorner to be bigger. I can't seem to find the right command for this.

The result I want is something like the symbol in the pictures. The second picture is from Evans and Gariepy. The third one is from Federer's Geometric Measure Theory, so I don't think they are just isolated notations.

• Could you post a picture of where you have seen that notation? In this document, for instance, the notation for the restriction of a measure \mu to a set A seems to be \left.\mu\right\rvert_A. Apr 6 '13 at 23:29
• @Jubobs You probably mean \mu\big|_{A} Apr 6 '13 at 23:34
• @egreg You must be right. The vertical bar is not a delimiter here... Apr 6 '13 at 23:35
• @Jubobs Not only that: \left. adds an unwanted space (and \right too). Apr 6 '13 at 23:36
• I have seen the Jubobs notation and the same but with a vertical harpoon instead of the vertical bar. But never seen that notation. Apr 7 '13 at 10:54

You can build the Evans and Gariepy notation with

\documentclass{article}

\usepackage{graphicx}

\newcommand{\measurerestr}{%
\,\raisebox{-.127ex}{\reflectbox{\rotatebox[origin=br]{-90}{$\lnot$}}}\,%
}

\begin{document}
$\mu\measurerestr A,$
\end{document}


• That's great. Thank you. So there isn't any predefined symbol for this... Apr 7 '13 at 12:36
• @BeniBogosel Never seen before. And texdoc symbols didn't reveal anything useful. Apr 7 '13 at 13:02

This shape is simple enough to build with rules:

\documentclass{article}

\newcommand{\mres}{\mathbin{\vrule height 1.6ex depth 0pt width
0.13ex\vrule height 0.13ex depth 0pt width 1.3ex}}

\begin{document}

$$\mu \mres B(A)$$

\end{document}


There is also \niv in the nath fonts.