# tikzcd : how to extended triangle with more arrows?

I have the following code which produces the attached triangle picture. Does anyone know how to produce a directed edge from S_0, down and to the right, ending at D_0b? Also, join vertexes S_1 and S_1 into a single vertex or point?

The tikz-cd documentation had little info on this shape and my own results led to many compilation failures. Appreciate any guidance on creating the shape.

Thanks

Note: I'm attempting to draw a Porphyry tree.

  \begin{tikzcd}[row sep=tiny]
& S_0 \arrow[dd, "\phi_1" description] \\
D_0 \arrow[ur, leftarrow] \arrow[dr, "\phi_2" description] \\
& S_1 \\
& S_1 \arrow[dd, "\phi_1" description] \\
D_1 \arrow[ur, leftarrow] \arrow[dr, "\phi_2" description] & \\
& S_2
\end{tikzcd}


• Hi, welcome. Perhaps I'm a bit slow, but I don't quite understand your first point. How should that edge look exactly? For the second point, simply delete the third row in your matrix, the one containing just & S_1 \\. – Torbjørn T. Apr 30 '19 at 19:03
• I corrected the description. The edge should go from S_0 to D_0b on the right. D_0b does not exist in the above picture – Nick May 1 '19 at 5:02

\documentclass{article}

\usepackage{tikz-cd}

\begin{document}
\begin{tikzcd}[row sep=tiny]
& S_0 \arrow[dd, "\phi_1" description]\ar[dr] \\
D_0 \arrow[ur, leftarrow] \arrow[dr, "\phi_2" description] &&D_{0b}\\
& S_1 \arrow[dd, "\phi_1" description]\ar[dr] \\
D_1 \arrow[ur, leftarrow] \arrow[dr, "\phi_2" description] &&D_{1b}\\
& S_2
\end{tikzcd}
\end{document}


• This looks good except I need to add a label to the right vertex at the end of the right edge. D0b. Then add the same below as another right edge to label D1b. I will try this. Thanks for interpreting this! – Nick May 1 '19 at 5:10
• @Nick See my renewed answer. – CarLaTeX May 1 '19 at 5:29

Is this what you want?

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

\begin{document}

\begin{tikzcd}[row sep=tiny]
& S_0\dlar \ar[dd, "\phi_1" description] \drar \\
D_0 \drar["\phi_2" description] & & D_{0b}\\
&S_1\dlar \arrow[dd, "\phi_1" description] \\
D_1 \drar["\phi_2" description] & \\
& S_2
\end{tikzcd}

\end{document}


• I vote you but apparently the question is not very clear. Your doubt has confirmed my hypothesis of unclearness. – Sebastiano Apr 30 '19 at 19:12
• Let's hope theO.P. will post some clarification!. I think the image is scanned from book, as it can't result from the posted code. – Bernard Apr 30 '19 at 19:15
• It could be because the characters are those of newtx package in text and/or mathematical mode. – Sebastiano Apr 30 '19 at 19:19
• The image resulted from the posted code. I have a lot of packages included also some for Greek text, which may substitute fonts from the system rather then ams ones. – Nick May 1 '19 at 5:12
• This looks correct except it needs a directed edge to the right with a label. I did not clarify this in the original post and updated accordingly. Thanks – Nick May 1 '19 at 5:13