# Curly line close together

I'm trying to find a symbol in LaTeX that looks like two curly vertical lines close together. Similar to,

\wr\wr


but closer together. Any help would be greatly appreciated. Many thanks!

• what is the purpose of this? (for example, does it decorate a "connector" in a commutative diagram?) is the shape you want essentially the same as \approx rotated 90 degrees? if that is the shape, then \rotatebox is probably the best approach. – barbara beeton Apr 9 '15 at 16:44
• It's to denote a seminorm - so a norm is $\|.\|$ (the dot is just a placeholder for some variable - it's the two straight lines that either side that denotes the norm). Essentially it is the \approx sign rotated 90 degrees. – Holtz Apr 9 '15 at 16:49
• @barbarabeeton - Many thanks - \rotatebox did the trick! – Holtz Apr 9 '15 at 16:57

Not that I like the symbol, but here it is:

\documentclass{article}

\newcommand\dblwr{\wr\mkern-2mu\wr}
\newcommand{\seminorm}[1]{\mathopen{\dblwr}#1\mathclose{\dblwr}}

\begin{document}

$\seminorm{x}$

\end{document}


• How come you don't like the symbol? – Holtz Apr 9 '15 at 18:45

From the comment of barbara beeton,

\documentclass{article}
\usepackage{graphicx}

\begin{document}

\rotatebox{90}{$\approx$}

\end{document}


Gives the desired output.

• I suggest you to use $\|\cdot\|$ instead of $\|.\|$, as you commented. – Sigur Apr 9 '15 at 17:28
• when you use it, you should also apply \mathopen and \mathclose as noted by @egreg, to get the correct spacing. – barbara beeton Apr 9 '15 at 18:10