Csdrhrt

I am using tikzcd.

I want to use line breaks within the label of the arrows. Naively, I thought that

begin{tikzcd}

  A arrow[d, "label 1 \ label 2"] \

  B

end{tikzcd}

would work. But it gives me

instead. How to solve this?

Use substack.

documentclass{article}

usepackage{amsmath}

usepackage{tikz-cd}



begin{document}



begin{tikzcd}[row sep=large]

  A arrow[d, "substack{a \ a}"] & % good

  A arrow[d,"a \ a" align=left] &  % bad

  A arrow[d,"shortstack{a\a}"]    % ugly

\

  B & B & B

end{tikzcd}



end{document}

If the labels are textual, use text inside substack. The same code as before, but with substack{text{a} \ text{a}} in the leftmost arrow yields

documentclass{book}

usepackage{tikz-cd,amsmath}

begin{document}

    begin{tikzcd}[row sep=3cm]

        A arrow[d, "shortstack{label 1\label 2}"] \

        B

    end{tikzcd}

end{document}

You only need to add align=left (or something of that sort).

documentclass{article}

usepackage{tikz-cd,amsmath}

begin{document}

begin{tikzcd}[row sep=3cm]

A arrow[d,"label1\ label2"align=left] \

B

end{tikzcd}

end{document}

From the pag. 13 of the guide of tikz-cd http://ctan.math.washington.edu/tex-archive/graphics/pgf/contrib/tikz-cd/tikz-cd-doc.pdf

I have used a matrix 2x1 (for example) to have two vertical labels. With the option row sep=...cm you can increase or decrease the lenght of the arrow.

documentclass[a4paper,12pt,oneside]{book}

usepackage{tikz-cd,amsmath}

begin{document}

begin{tikzcd}[row sep=2cm, ampersand replacement=&]

A arrow[d, "{begin{matrix} text{label1} \ text{label2} end{matrix}}

"] \

B

end{tikzcd}

end{document}