code for commutative diagrams

Question

There are some diagrams which are little bit complicated, I use array package to draw basic ones I mean square ones. but is it possible to draw any diagram by [array] package? for example can you help me in this, thin i can mimic the same way Thanks a lot

Answer 1

A rather nice diagram is obtained with tikz-cd:

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

\begin{document}

\[
\begin{tikzcd}[column sep=2.5pc,row sep=2pc]
{} & B \arrow{d} \arrow[bend left]{dddrr} \\
A \arrow{r} \arrow{rrd} \arrow[bend right]{rrrdd} & G \\
{} & {} & P \arrow{ul}[swap]{\tilde{\varphi}} \\
{} & {} & {} & B*C \arrow{ul}[swap]{\nu}
\end{tikzcd}
\]

\end{document} 

Answer 2

You could try the xypic package. See this page for manuals and documentation.

Answer 3

Or else using the tikz positioning library

Here's the code:

% arara: pdflatex

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{positioning}

% arrows set as stealth fighters
\tikzset{>=stealth}

\begin{document}

\begin{tikzpicture}
    % setup the nodes
    \node (B){$B$};
    \node[below=of B](G){$G$};
    \node[left=of G](A){$A$};
    \node[below right=of G](P){$P$};
    \node[below right=of P](BstarC){$B*C$};
    % connect them
    \foreach \start/\finish/\mylabel in {B/G/, A/G/, A/P/, P/G/$\tilde{\varphi}$, BstarC/P/$\nu$}
    {
        \draw[->](\start)--(\finish) node[midway,above]{\mylabel};
    }
    % bended arrows
    \draw[->](A) to[bend right=30] (BstarC);
    \draw[->](BstarC) to[bend right=20] (B);
\end{tikzpicture}

\end{document}