4

Here is the diagram I want to draw:

enter image description here

I got a help on drawing the following from here :

\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{cd}

\begin{document}
    $$\begin{tikzcd}
        & P \ar[dl, dashed, "\tilde{f}" ']
        \ar[d, "f"]     \\
        A \ar[r,twoheadrightarrow,"g" ']    & B 
    \end{tikzcd}$$
\end{document}

But how can I put the arrow with the 0 in this diagram? could someone show me this please?

3 Answers 3

4
\documentclass{article}

\usepackage{tikz}
\usetikzlibrary{cd}

\begin{document}
    \[\begin{tikzcd}
        & P \ar[dl, dashed, "\tilde{f}" ']
        \ar[d, "f"]     \\
        A \ar[r,twoheadrightarrow,"g" ']   & B  \arrow[r, twoheadrightarrow] & 0
    \end{tikzcd}\]
\end{document}

enter image description here

1
  • 2
    Don't use $$ in LaTeX! Instead them use \[ and \] respectively.
    – Zarko
    Commented Feb 15, 2021 at 6:19
7

The original figure, I think, it is done with package. In fact the classic tips are the same. The font used it is (mtpro2) where in this link you can find the version lite.

I have changed the font with newtxtext (clone of Times New Roman) and newtxmath. I think that it is very close with your image.

\documentclass[a4paper,12pt]{article}
\usepackage[all]{xy}
\usepackage{newtxtext,newtxmath}
\begin{document}
\xymatrix@R=2pc@C=3pc{
& P \ar[d]^{id} \ar@{-->}[dl]_{\mu} &\\
M \ar[r]^{\varphi} & P\ar[r] & 0
}

\end{document}

enter image description here

Addendum 1: ## To have the twoheadrightarrow you can use the code \ar@{>>} (see the MWE):

\documentclass[a4paper,12pt]{article}
\usepackage[all]{xy}
\usepackage{newtxtext,newtxmath}
\begin{document}
\xymatrix@R=2pc@C=3pc{
& P \ar[d]^{id} \ar@{-->}[dl]_{\mu} &\\
M \ar@{>>}[r]^{\varphi} & P\ar@{>>}[r] & 0
}
\end{document}

enter image description here

If you want the tips of you can use the options [all, cmtip]:

\documentclass[a4paper,12pt]{article}
\usepackage[all,cmtip]{xy}
\usepackage{newtxtext,newtxmath}
\begin{document}
\xymatrix@R=2pc@C=3pc{
& P \ar[d]^{id} \ar@{-->}[dl]_{\mu} &\\
M \ar@{>>}[r]^{\varphi} & P\ar@{>>}[r] & 0
}
\end{document}

enter image description here

4

Another possible answer than @Roland's, would be to use \usetikzlibrary{matrix}. That would look like

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{matrix}

\begin{document}
    \begin{tikzpicture}%
        \matrix[matrix of math nodes,row sep=1cm, column sep=1cm]{%
            && |(P)| P \\
            & |(M)| M & |(Ptwo)| P & |(zero)| 0 \\
        };%
        \draw[dashed,->,very thick](P)--(M) node[above,pos=0.5]{\(\mu\)};%
        \draw[->>,very thick](P)--(Ptwo) node[right,pos=0.5]{id};%
        \draw[->>,very thick](M)--(Ptwo) node[above,pos=0.5]{\(\varphi\)};%
        \draw[->,very thick](Ptwo)--(zero);%
    \end{tikzpicture}%
\end{document}

That would give the display:

enter image description here

Nota Bene: You can play around and change [row sep=1cm, column sep=1cm] to modify the spacing and make it as you wish.

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