Subscript for Norms are too high

Question

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?

score 9 · Accepted Answer · answered Jan 16 '14 at 13:57

9

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

enter image description here

answered Jan 16 '14 at 13:57

karlkoeller

124,410

Is there a variable that sets how high/low a subscript is placed? – Chrystomath Jan 17 '14 at 07:17
@Chrystomath Not that I know – karlkoeller Jan 17 '14 at 07:35
@karlkoeller Can it be done without mathtools and/or pairedDelimiter? Because those don't work for me. – cgss Nov 05 '20 at 15:02
The MWE does not work for me (MiKTeX, mathtools 1.29): both subscripts are the same height. – PHPirate Sep 15 '22 at 13:02

score 3 · Answer 2 · answered Jan 16 '14 at 13:54

3

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}

enter image description here

answered Jan 16 '14 at 13:54

1

Nice to meet you. I'm a mathematician. – Sigur Jan 16 '14 at 14:09

score 1 · Answer 3 · answered Jan 16 '14 at 13:50

1

Is this what you want?

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

a$\norm{x}_Mx_M$a

enter image description here

answered Jan 16 '14 at 13:50

Sigur

37,330

Subscript for Norms are too high

3 Answers3

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