# drawing a specific diagram

First of off: I have to say sorry for this dumb question. How to draw the diagram http://msp.org/pjm/1982/98-2/pjm-v98-n2-p15-s.pdf on page 6, which can be found in the proof of proposition 2.4 using tikzpicture or tikzcd and for documentclass{article}?

I have tried to follow instructions on several websites, and I have tried to modify examples like this http://texample.net/tikz/examples/commutative-diagram-tikz/ so far. I usually can do it by myself, but this time nothing works.

Greetings

• Welcome to TeX.SX! What have you tried so far (please show a minimal compilable code example)? We usually do not answer questions that sound like do-it-for-me. – TeXnician Aug 14 '17 at 17:36
• oh, sorry! I will keep that in mind and share my attempts from now on! Furthermore, I'm going to improve this question soon. – Kashvi Ramaprasad Aug 14 '17 at 17:49

## 1 Answer

You should think to the diagram as a three row and two column matrix. You add arrows in the cell where they start from, stating the target and the possible label.

In the present case, the label is \textstyle\cong; for it you specify "\textstyle\cong"'; the trailing apostrophe tells tikz-cd to place the label on the right side of the arrow: you should think to arrows like rivers, so you determine the right and left side by virtually placing yourself with the back to the source and the face to the end.

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

\begin{document}

$\begin{tikzcd} K_*\varinjlim(A_\gamma)\otimes K_*(B) \arrow[r,dashed] & K_*((\varinjlim A_\gamma)\otimes B) \\ \varinjlim(K_*A_\gamma)\otimes K_*(B) \arrow[u,"\textstyle\cong"'] & K_*(\varinjlim (A_\gamma\otimes B)) \arrow[u,"\textstyle\cong"']\\ \varinjlim((K_*A_\gamma)\otimes K_*(B)) \arrow[u,"\textstyle\cong"'] \arrow[r] & \varinjlim K_*(A_\gamma\otimes B) \arrow[u,"\textstyle\cong"'] \end{tikzcd}$

\end{document}