Clash with dutch Babel and tikzcd

Question

I was trying to make a commutative diagram using something like \arrow[r, "A"] at some point, and I kept getting weird errors. I finally found out that I got no errors if I removed "dutch" from \usepackage[dutch, english]. Alternatively, I can get it to work by enclosing the tikzcd environment with \shorthandoff{"}...\shorthandon{"}. Apparently, something in "dutch" clashes with the use of " in \arrow[r, "A"]. Two questions.

• What is exactly the clash here? What is "predefined" or whatever in the dutch option in babel that does not like the use of "" in the arrow command?

• Is there a nicer solution to this problem? The only thing I can think of is to redefine the tikzcd environment to be something like

\shorthandoff{"}\begin{tikzcd}...\end{tikzcd}\shorthandon{"}

This is really just wrapping the earlier inelegant solution in a large blanket, so I'm not a fan.

Loading tikzlibrary{babel} solves the issue if one does not wrap the tikzcd in an align environment (and there is not a good reason to do this). I'm still curious what exactly align messes up here, though.

After all, a MWE. I do something like this.

\documentclass{report}

\usepackage[a4paper]{geometry}

\usepackage{libertine}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[dutch, english]{babel}

\usepackage{mathtools}

\usepackage{tikz}
    \usetikzlibrary{cd}
    \usetikzlibrary{babel}

\begin{document}

\begin{align*}
    \begin{tikzcd}[ampersand replacement = \&]
        A \arrow[r, "A"] \& B
    \end{tikzcd}
\end{align*}

\end{document}

Answer 1

First some general words. We invite to present the question with a minimal example of code for several reasons:

• often the question is presented with no hint about the actual error message(s);
• preparing a MWE sometimes helps in spotting the error or in finding a workaround;
• it's kind to whoever wants to help.

More specific to your post, you probably had two sources for errors. One due to babel making " active for Dutch, the other one because of using tikzcd inside an align environment.

Solution for the first problem: \usetikzlibrary{babel}.

Solution for the second problem: use the ampersand replacement=\& option and \& in the body of tikzcd to mark column delimiters. But also \shorthandoff{"} and \shorthandon{"}.

Why is that? Because align (and the other amsmath display environments) absorb the contents as the argument to a macro and so tikzcd cannot do the trick it usually does to &. Neither it can do the job for ".

If you're used to generally employ align or align* for single equation (or diagram), change your habit and use equation or equation* in these cases. It's semantically sounder, more efficient and avoids doing some tricks. Moreover, the spacing is better. I guess you can spot below the difference in spacing, which is excessive with align*.

\documentclass{article}

\usepackage[T1]{fontenc}
\usepackage[dutch, english]{babel}

\usepackage{mathtools}

\usepackage{tikz-cd}
\usetikzlibrary{babel}

\usepackage{lipsum} % for mock text

\begin{document}

\lipsum[2][1-2]
\begin{equation*}
    \begin{tikzcd}
        A \arrow[r, "A"] & B
    \end{tikzcd}
\end{equation*}
\lipsum[2][1-2]
\shorthandoff{"}\begin{align*}
    \begin{tikzcd}[ampersand replacement = \&]
        A \arrow[r, "A"] \& B
    \end{tikzcd}
\end{align*}\shorthandon{"}%
\lipsum[3]

\end{document}

Answer 2

My answer is off-topic with the tags I hope to have understood your request. I have used xy package without the hard tip arrows 😉 with the options [all,cmtip] leaving your babel \usepackage[dutch]{babel}.

PS: I have only thinked an alternative.

\documentclass[a4paper,12pt]{article}
\usepackage[a4paper]{geometry}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[dutch,english]{babel}
\usepackage{mathtools}
\usepackage[all,cmtip]{xy}

\begin{document}
One morning, when Gregor Samsa woke from troubled dreams, he found himself transformed in his bed into a horrible vermin. He lay on his armour-like back, and if he lifted his head a little he could see his brown belly, slightly domed and divided by arches into stiff sections. 
\begin{align*}
\xymatrix@1{
A\ar[r]^A & B}  
\end{align*}
The bedding was hardly able to cover it and seemed ready to slide off any moment.
\begin{align*}
\xymatrix@1{
A\ar[r]^A & B}  
\end{align*}
Gregor then turned to look out the window at the dull weather. Drops
\end{document}