Fixing a Commutative Diagram

Question

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!

Answer 1

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}