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I have the following commutative diagram made using tikz-cd.enter image description here

Here is the code:

\documentclass[preview]{standalone}     
\usepackage{geometry}                       
\geometry{letterpaper}                          
\usepackage{graphicx}                   
\usepackage{amssymb}
\usepackage{tikz-cd}

\def\Z{\mathbb{Z}}


\begin{document}


$$
 \begin{tikzcd}[]
1 \arrow{r} & A_3 \arrow[hookrightarrow]{r}\arrow[equal]{d} & S_3 \arrow{r}{\textrm{sign}} & \langle \pm 1 \rangle\arrow[equal]{d} \arrow{r} & 1\
1 \arrow{r} &\Z/3\Z\arrow{r} & \Z/6\Z \arrow{r} & \Z/2\Z\arrow{r} & 1
\end{tikzcd}
$$


\end{document}

I want to show that S3 is not isomorphic to Z/6Z by a not equals sign or something of the sort. How would I do that?

user227788
  • 23
  • Welcome to TeX.SX! It will be really helpful if you put here the code that you already have. This way, others can take your code, and add whatever is needed to solve your problem, rather than answering with a partial example or recoding your diagram. – Vincent Oct 28 '20 at 17:16
  • My bad. Thanks for letting me know; the code has been added. – user227788 Oct 28 '20 at 17:32
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    Unrelated: You should use \[ ... \] instead of $$ ... $$, cf. https://tex.stackexchange.com/questions/503/why-is-preferable-to – DG' Oct 28 '20 at 18:14
  • @DG' Thank you for letting me know; I will employ that practice from now on. – user227788 Oct 28 '20 at 21:39

1 Answers1

2

You can overlay arbitrary symbols with the option marking. Here I used / as the symbol, but you might want to choose another one that is fitting your needs / aesthetic preferences better :

\documentclass[preview]{standalone}     
\usepackage{geometry}                       
\geometry{letterpaper}                          
\usepackage{graphicx}                   
\usepackage{amssymb}
\usepackage{tikz-cd}

\def\Z{\mathbb{Z}}


\begin{document}


[
  \begin{tikzcd}
    1 \arrow{r} & A_3 \arrow[hookrightarrow]{r}\arrow[equal, "/" marking]{d} & S_3 \arrow{r}{\textrm{sign}} & \langle \pm 1 \rangle\arrow[equal, "/" marking]{d} \arrow{r} & 1\
    1 \arrow{r} &\Z/3\Z\arrow{r} & \Z/6\Z \arrow{r} & \Z/2\Z\arrow{r} & 1
  \end{tikzcd}
]


\end{document}

enter image description here

DG'
  • 21,727