# Subscript for Norms are too high

I'm defining \norm by \|#\|. However, when I type \norm{x}_{M}, the M comes out at exactly the same height as if one typed x_M. The problem is really noticeable with upper-case subscripts. Is there a way to modify the \norm definition so that the subscript M is lowered slightly below \| and truly appears as its subscript?

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If you want to define it yourself, it is better with the help of \DeclarePairedDelimiter from mathtools:

\DeclarePairedDelimiter{\norm}{\lVert}{\rVert}


MWE

\documentclass{article}
\usepackage{mathtools}
\DeclarePairedDelimiter{\norm}{\lVert}{\rVert}
\begin{document}
$\norm{x}_Mx_M$
\end{document}


Output

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Is there a variable that sets how high/low a subscript is placed? – Chrystomath Jan 17 '14 at 7:17
@Chrystomath Not that I know – karlkoeller Jan 17 '14 at 7:35

I hate re-inventing (Because I am lazy). With physics package:

\documentclass{article}
\usepackage{physics}
\begin{document}
$a\norm{x}_{M}a$
$a\abs{x}_{M}a$
\end{document}


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+1. Thanks for introducing me physics. – Sigur Jan 16 '14 at 13:57
@Sigur Thanks. I am a physics teacher ;-) – Harish Kumar Jan 16 '14 at 14:04
Nice to meet you. I'm a mathematician. – Sigur Jan 16 '14 at 14:09

Is this what you want?

\newcommand{\norm}[1]{\left\|#1\right\|}

a$\norm{x}_Mx_M$a


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