# Curved arrow linking flow diagram

I would like to draw something like this:

A ---> B ---> C and then have a curved arrow underneath going from A to C (and I will need to have a superscript on all the arrows to include a label).

I understand that this is possible with the xyarray package? But all of the examples on here seem much more complicated than the simple case that I want.

Can anybody help?

Thanks a lot

It's also very simple with tikz-cd:

\documentclass[12pt]{article}
\usepackage{tikz-cd}

\begin{document}

\begin{tikzcd}
A\rar{u}\arrow[red, bend right]{rr}[black,swap]{\varphi}  & B \rar{v}  & C
\end{tikzcd}

\end{document}


• I made an edit only to fix the code markup. Nice answer! – Arun Debray Jul 7 '16 at 19:08
• Thanks :o) What was the problem? – Bernard Jul 7 '16 at 19:17
• the first line was set as ordinary text instead of code; nothing huge. – Arun Debray Jul 7 '16 at 20:01
• Must have been really out of my mind… – Bernard Jul 7 '16 at 20:09
• @Bernard Thanks, is there a way to reduce white space underneath the diagram so I can continue text without an overly large gap? – user11128 Jul 8 '16 at 11:42

Yes, it is possible with Xy, and is fairly simple:

\documentclass{article}
\usepackage[all]{xy}
\begin{document}
$\xymatrix{ A \ar[r] \ar@/_0.4cm/[rr] & B \ar[r] & C }$
\end{document}


Just as in a matrix or array environment, the content of an xymatrix is interpreted as a grid, with & separating entries and \\ separating rows. \ar is the command for an arrow: [r] indicates that it points to the right.

The most complicated part is the curved arrow: starting with \ar[rr] (an arrow pointing two grid entries to the right), the syntax @/_0.4cm/ signals to curve it downwards by 0.4 cm.

Output:

Then, you can label your arrows with superscripts and subscripts: \ar[r]^f typesets f above the arrow, and \ar[r]_g typesets g below the arrow. (If you use arrows pointing other directions, this will change: technically, ^ is used to put the label on the left side of the arrowhead, and _ on the right side.)