# Using arrows in an alignment

I would like to do something like the following. I am wondering if tikz-pgf would be the right tool to use.

Except the (E.G.) should not be there. I'm pretty sure that is a typo.

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Can you at least provide the bare code that you want to write over? Please add a minimal working example (MWE) that illustrates your problem. –  percusse Nov 7 '12 at 20:02
Yes, tikz is perfect for this. See for example: tikz arrow outside tikzpicture environment. There is an example on this site with an image (as far as the arrow) pretty much identical to yours, but can't seem to find it right now. –  Peter Grill Nov 7 '12 at 20:15

If you do your alignment using a tikzpicture, you can do something like this:

\documentclass[a4paper]{article}

\usepackage{amssymb}
\usepackage{tikz}
\usetikzlibrary{positioning}

\begin{document}

\textbf{Universal Generalization (U.G.)}

\begin{tikzpicture}
\node (a) {flag $a$};
\node[below=.5ex of a] (b) {$\cdot$};
\node[below=.5ex of b] (c) {$\cdot$};
\node[below=.5ex of c] (d) {$\cdot$};
\node[below=.5ex of d,anchor=north east] (e) {$\phi a$};
\node[below=5ex of d] (f) {$(x)\phi x$};
\node[left=.5ex of f] (g) {$/\therefore$};
\draw[->] (e.south east) -- (e.south -| g.west) |- (a);
\draw (g.north west) -- (f.north east);
\end{tikzpicture}

\end{document}


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