# Fixing a Commutative Diagram

I am using the xymatrix command...

If I type the following code

\documentclass[11pt,oneside,a4paper,fleqn]{report}
\usepackage[all,cmtip]{xy}
\begin{document}
$\xymatrix{ 0 \ar[r] & A \ar@{^{(}->}[r]& B \ar[r] \ar[d] & C \ar[d] \\ D \ar[r] & E \ar[r] & F \ar[r] \ar[ru] & G }$
\end{document}


everything works great...

The thing is, however, that I want to get rid of $D$ and $E$ in the lower row... i.e. I want to have two rows of exact sequences with only the box on the left... but if I just delete the section D \ar[r] & E \ar[r] &, I get an error!

What should I do?

Thanks!

• Please help us to help you and add a minimal working example (MWE) that illustrates your problem. It will be much easier for us to reproduce your situation and find out what the issue is when we see compilable code, starting with \documentclass{...} and ending with \end{document}. – user31729 Jun 9 '14 at 8:27

Just leave an empty cell:

\documentclass[11pt,oneside,a4paper,fleqn]{report}
\usepackage[all,cmtip]{xy}
\begin{document}
$\xymatrix{ 0 \ar[r] & A \ar@{^{(}->}[r] & B \ar[r] \ar[d] & C \ar[d] \\ & & F \ar[r] \ar[ru] & G }$
\end{document}


Here's the tikz-cd version:

\documentclass[11pt,oneside,a4paper,fleqn]{report}
\usepackage{tikz-cd}
\begin{document}
$\begin{tikzcd} 0 \arrow{r} & A \arrow[hook]{r} & B \arrow{r} \arrow{d} & C \arrow{d} \\ & & F \arrow{r} \arrow{ru} & G \end{tikzcd}$
\end{document}