# How do I realize an arrow representing “line numbers” in LyX?

I want to draw an arrow, who shall represent line numbers like in the following screenshot.

I struggeled with xymatrix, but this doesn't seem to be the right approach. Any ideas?

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This kind of drawing would be relatively easy to draw in tikz. – gerrit Nov 1 '12 at 22:33

As mentioned in the comments, this is pretty straight forward using tikz; here's something to get you started

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{decorations.pathreplacing}
\usetikzlibrary{calc}

\begin{document}
\begin{tikzpicture}
% draw the arrow
\draw[->](0,0)--(10,0);
% draw the tick marks
\foreach \x/\nodename/\mytext in {1/a/$2(N-1)\omega$,5/b/$2N\omega$,7/c/$2\omega_0$,9/d/$2(N+1)\omega$}
\draw[shift={(\x,0)},color=black] (0pt,2pt) -- (0pt,-2pt) node[anchor=north](\nodename){\mytext};
% draw the braces
\draw[decorate,decoration={brace,amplitude=10}]($(a.north)+(0,.25)$)--($(b.north)+(0,.25)$)node[anchor=south,pos=.5,outer sep=.5cm]{$|2\omega|$};
\draw[decorate,decoration={brace,amplitude=10}]($(b.north)+(0,.25)$)--($(c.north)+(0,.25)$)node[anchor=south,pos=.5,outer sep=.5cm]{$|2\omega_0-2N\omega|$};
\end{tikzpicture}
\end{document}


Notes

I hope that most of the code is pretty self-explanatory; one of the pieces that isn't immediately obvious (to someone who hasn't seen a lot of tikz code) is the line

\foreach \x/\nodename/\mytext in {1/a/$2(N-1)\omega$,5/b/$2N\omega$,7/c/$2\omega_0$,9/d/$2(N+1)\omega$}


The way that I read this is to think that \x, \nodename, and \mytext are all loop variables, and they will take the values specified in the following curly braces (separated by the delimeter /).

So

• \x will take the values 1,5,7,9
• \nodename will take the values a,b,c,d
• \mytext will take the values $2(N-1)\omega$,...,$2(N+1)\omega$

I've used

• \usetikzlibrary{decorations.pathreplacing} for the braces; the amplitude key controls the amplitude of the brace
• \usetikzlibrary{calc} to tweak the vertical positioning of the braces, for example ($(a.north)+(0,.25)$) means to use the node named a north's position PLUS (0,.25)

The tikz package provides a huge number of tools, so there are probably multiple ways to do this- my code is just one such way :)

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