Arrows for morphisms of exact sequences

Question

I'm trying to figure out a good way to use LaTeX to draw the following diagram (snapshot image from a document).

The closest I could come to this is using the following code:

\begin{align}
\begin{array}{ccccccccc}
  0 &\xlongrightarrow & M' & \xlongrightarrow & M & \xlongrightarrow & M'' & \xlongrightarrow & 0\\
  & & \bigg\downarrow & & \bigg\downarrow & & \bigg\downarrow & & \\
  0 &\xlongrightarrow & N' & \xlongrightarrow & N & \xlongrightarrow & N'' &  \xlongrightarrow & 0
\end{array}
\end{align}

which renders to the following picture:

Using the array and align environment does not seem like a good thing to do. Is there a more efficient way to make such a diagram with arrows? I have seen similar posts which suggest TikZ, but I don't know much about it -- maybe I'll learn it. But multiple solutions or pointers in the right direction will be very welcome.

What about arrows at angles (say something from $M'$ in the first row to $N$ in the second row -- it makes no sense in the context here, but I'd like to be able to make such arrows easily, with little modification to the code needed in case of changes)?

Once you've dabbled a bit with TikZ, you'll find it well suited to this kind of diagram. And then you can do things like the Snake Diagram http://tex.stackexchange.com/q/3892/86 — Andrew Stacey, Nov 13 '16 at 19:23

CarLaTeX · Accepted Answer · 2016-11-13T19:18:31.547

8

If you like a TikZ solution (with also the diagonal arrow):

\documentclass{article}
\usepackage{tikz-cd}
\begin{document}
    \begin{tikzcd}%
        0 \arrow[r] & M' \arrow[r] \arrow[d] \arrow[rd] & M \arrow[r]  \arrow[d] & M'' \arrow[r] \arrow[d]  & 0 \\  
        0 \arrow[r] & N' \arrow[r]  & N \arrow[r]  & N'' \arrow[r]  & 0 
    \end{tikzcd}%
\end{document}

edited Nov 13 '16 at 19:18

answered Nov 13 '16 at 18:55

CarLaTeX

62,716

2

@leastaction You're welcome! As you can see, it is very simple. – CarLaTeX Nov 13 '16 at 20:13

score 3 · Answer 2 · answered Nov 13 '16 at 17:42

Here is a simple solution. The long right arrows are produced with hboxes. You can adapt the length; I chose here 1cm.

\documentclass{article}

\usepackage{amsmath}

\newcommand{\Lrightarrow}{\hbox to1cm{\rightarrowfill}}
\newcommand{\Ldownarrow}{\bigg\downarrow}


\begin{document}

\[
  \setlength{\arraycolsep}{1pt}
  \begin{array}{*{9}c}
    0 &\Lrightarrow & M' & \Lrightarrow & M & \Lrightarrow & M'' & \Lrightarrow & 0\\
    & & \Ldownarrow & & \Ldownarrow & & \Ldownarrow & & \\
    0 &\Lrightarrow & N' & \Lrightarrow & N & \Lrightarrow & N'' &  \Lrightarrow & 0
  \end{array}
\]

\end{document}

score 2 · Answer 3 · answered Nov 13 '16 at 22:56

Using the amscd package gives similar results, though diagonal arrows are not supported:

\documentclass{article}
\usepackage{amscd}
\begin{document}
\[
\begin{CD}
0 @>>> M' @>>> M @>>> M'' @>>> 0 \\
@. @VVV @VVV @VVV \\
0 @>>> N' @>>> N @>>> N'' @>>> 0
\end{CD}
\]
\end{document}

score 1 · Answer 4 · answered Dec 06 '16 at 01:21

Here is a solution using the xy-pic package, including a diagonal arrow:

\documentclass{article}
\usepackage[all]{xy}
\begin{document}
\xymatrix{
0 \ar[r]    & M' \ar[d]\ar[r] \ar[dr]   & M \ar[d]\ar[r]    & M'' \ar[d]\ar[r]  & 0 \\
0 \ar[r]    & N' \ar[r]                 & N \ar[r]          & N'' \ar[r]        & 0
}
\end{document}

XY-pic User's Guide

Arrows for morphisms of exact sequences

4 Answers4