# Multiple arrows to an object

I am trying to figure out how to make several arrows point to a particular object. For example if I am wanting to have an arrow $A_i \rightarrow A A_j \rightarrow A$ and $A_k \rightarrow A$ and $A_i \rightarrow A_j$ in a diagram. I have worked out how to do:

\begin{equation*}
\xymatrix@C+2em@R+2em{
A_i  \ar[d]_{f^{i}} & B_i \ar[d]^{h^{i}} \\
A \ar[r]_{\phi} & B
}
\end{equation*}


But I don't know how to modify this to get what I want (and I can't seem to find examples using the equation* or other workable examples.

Thanks,

Brian

-
It would be useful to have a MWE. I have no idea what \ar or \xymatrix@C+2em@R+2em are about. It looks like you're trying to use \xymatrix@C as a macro, but that's generally not a valid macro naming convention in the body of a document. –  A.Ellett Mar 1 '14 at 16:23
Can you please add to your question an image of the desired output? It's not clear from the code snippet you posted the desired position for the objects and arrows. –  Gonzalo Medina Mar 1 '14 at 16:30

Using the more modern tikz-cd package, you can do:

\documentclass{article}
\usepackage{amsmath}
\usepackage{tikz-cd}

\begin{document}

\begin{tikzcd}
A_i
\ar{dr}[swap]{f^{i}}
\ar{r}{h}
&
A_j
\ar{d}[swap]{f^{j}}
&
A_k
\ar{dl}{f^{k}} \\
& A
\end{tikzcd}

\begin{tikzcd}
A_i
\ar{dr}{f^{i}}
\ar{d}[swap]{h}  \\
A_j\ar{r}[swap]{f^{j}} & A
\\
A_k
\ar{ur}[swap]{f^{k}} \\
\end{tikzcd}

\end{document}


-
Thank you Gonzalo. Is it using the the tikz-cd package that makes this more of a modern approach? I have seen it around, thanks for the example using it! What are the benefits of using this package as opposed to the {all}[xy]? –  user1922184 Mar 8 '14 at 2:22
@user1922184 tikz-cd allows you to use all the power of TikZ, so yes, tikz-cd it's a more modern and versatile package for commutative diagrams. –  Gonzalo Medina Mar 8 '14 at 2:24
I put this as the answer because it uses tikz-cd and the [all]{xy} wasn't working so well. –  user1922184 May 7 '14 at 1:31
Also, after some amounts of messing around with the tikz pdf examples here: jmilne.org/not/Mtikz.pdf I am wondering.. what if I want to change the right arrow i.e. \arrow{r} to an implies $\Leftrightarrow$? Now your example works great and I am trying to not have to use the examples in the article using \path as it seems to be a whole different format which is quite more complicated. So is there a abbreviation for the iff? Even better, could I somehow use your example and just include latex directly in ie. such as the $\Leftrightarrow$ mentioned? –  user1922184 May 7 '14 at 1:49
@user1922184 Refer to the tikz-cd package documentation to see the different type of arrows already available. You can use \Leftrightarrow directly, as in \begin{tikzcd} A\ar[r,Leftrightarrow] & B \end{tikzcd} –  Gonzalo Medina May 7 '14 at 1:56

Do you mean something like this?

Code:

\documentclass{article}
\usepackage{amsmath}
\usepackage[all]{xy}

\begin{document}

\begin{equation*}
\xymatrix@C+2em@R+2em{
A_i \ar[r]^{\phi} \ar[dr]_{f^{i}} & A_j \ar[d]^{f^{j}} & A_k \ar[dl]^{f^{k}} \\
& A
}
\end{equation*}

\end{document}


or

Code:

\documentclass{article}
\usepackage{amsmath}
\usepackage[all]{xy}

\begin{document}

\begin{equation*}
\xymatrix@C+2em@R+2em{
A_i \ar[d]_{\phi} \ar[dr]^{f^{i}} \\
A_j \ar[r]^{f^{j}} & A \\
A_k \ar[ur]_{f^{k}}
}
\end{equation*}

\end{document}

-
I'm completely unfamiliar with this package xy. And texdoc xy doesn't really pull up much useful about things like \xymatrix..... Where do I go to find documentation? –  A.Ellett Mar 1 '14 at 16:36
@A.Ellett xy-pic.sourceforge.net and go to the documenation section. –  Gonzalo Medina Mar 1 '14 at 16:49
@A.Ellett texdoc xypic –  karlkoeller Mar 1 '14 at 16:57