# Array of numbers with arrows

In Principles of Mathematical Analysis, Walter Rudin utilizes the following array of numbers:

I want to recreate it in TeX but I don't even know how to start. Can someone help me?

EDITED: I tried to edit some of the answers in post cited in Alenanno's comment. It kinda worked, but I couldn't make the arrows parallel.

My attempt:

$$\begin{array}{*{6}{c}} & \tikzmark{e1}x_{11}\tikzmark{s1} & x_{12}\tikzmark{s2} & x_{13}\tikzmark{s3} & \cdots \\ \\ & \tikzmark{e2}x_{21} & x_{22} & x_{23}\tikzmark{s4} & \cdots \\ \\ & \tikzmark{e3}x_{31} & \tikzmark{e4}x_{32} & \tikzmark{e5}x_{33}\tikzmark{s5} & \cdots \\ & \vdots & \vdots & \vdots & \ddots \\ \end{array}$$
\begin{tikzpicture}[overlay,remember picture]
\foreach \i in {1,2,...,5}
\draw[<-] ($(s\i.north east)+(-0.1,0.1)$) -- ($(e\i.south west)+(0.1,0)$);
\end{tikzpicture}

• 'Just' the array or also the diagonal lines? – user31729 Aug 26 '16 at 18:47
• Related (possible duplicates): Drawing Multiple Diagonal Arrows in a Table, Drawing Arrows in Tables. – Alenanno Aug 26 '16 at 18:48
• Please try the solutions inside of those linked questions. It shouldn't be hard to edit those. If you still have problems, you can edit your question showing what you're having trouble with. – Alenanno Aug 26 '16 at 18:54
• Edited the post. Christian, the array is easy to do. I couldn't figure out the diagonal lines. – Gabriel Aug 26 '16 at 19:26
• @GabrielRibeiro: Yes, but please don't use  -- that's outdated syntax. Use $....$ instead if you need display math style – user31729 Aug 26 '16 at 20:08

One way would be to use the TikZ matrix library. The arrows may be added using a simple loop and the automatic names assigned by the matrix of nodes operation.

\documentclass[border=10pt,multi,tikz]{standalone}
\usetikzlibrary{matrix}
\begin{document}
\begin{tikzpicture}
\matrix (m) [matrix of math nodes]
{
x_{11} & x_{12} & x_{13} & x_{14} & \dots \\
x_{21} & x_{22} & x_{23} & x_{24} & \dots \\
x_{31} & x_{32} & x_{33} & x_{34} & \dots \\
x_{41} & x_{42} & x_{43} & x_{44} & \dots \\
\dots \\
};
\foreach \i in {1,...,4} \draw [->] (m-\i-1.south west) -- (m-1-\i.north east);
\end{tikzpicture}
\end{document}