Argthtjtr

I am trying this:

documentclass[10pt]{article}



usepackage{amsmath,amssymb,tikz-cd}



begin{document}



begin{equation*}

begin{tikzcd}[row sep=huge]



A arrow[r, "aaa"] arrow[d, "xxxx"] &   B  arrow[d, "yyyy"] \ 



C                           & D  arrow[l, "bbbbbbbbbbbbbbbbb"] \



end{tikzcd}



end{equation*}



end{document}

and I would like to fix 2 things:

1) The arrow over the "bbbbbbbbbbbbbbbbbbbb" label should be longer, so the pic does not look so cramped.
2) I would like the "xxxx" label to be on the left of the down arrow.

Thank you.

Like this?

documentclass[10pt]{article}



usepackage{amsmath,amssymb,tikz-cd}



begin{document}



begin{equation*}

begin{tikzcd}[row sep=huge,column sep=width("bbbbbbbbbbbbbbbbb")]

A arrow[r, "aaa"] arrow[d, "mathrm{xxxx}" swap] &   B  arrow[d,

"mathrm{yyyy}"] \ 

C                           & D  arrow[l, "bbbbbbbbbbbbbbbbb"] \

end{tikzcd}

end{equation*}



end{document}

From the TikZ manual, Section 20.3.2 Setting and Adjusting Column and Row Spacing

The cell separation character & also takes an optional argument, which
must also be a spacing list. This spacing list is added to the column
sep having a similar effect as the option for the \ command for rows.

This optional spacing list can only be given the first time a new
column is started (usually in the first row), subsequent usages of
this option in later rows have no effect.

In practice, if you put a [<width>] after &, for example &[7em], you can enlarge the space between the two columns separated by &[<width>] as you wish.

The option column sep=<width> sets a default spacing for all columns.

This difference could be relevant in case you have a matrix with more than two columns. If you want to enlarge only the space between the first and the second columns, but not between the second and the third, &[<width>] should be used, not column sep=<width>.

Option swap to change the position of the label.

documentclass[10pt]{article}



usepackage{amsmath,amssymb,tikz-cd}



begin{document}



begin{equation*}

begin{tikzcd}[row sep=huge]

A arrow[r, "aaa"] arrow[d, "xxxx", swap] &[7em]   B  arrow[d, "yyyy"] \ 

C                           & D  arrow[l, "bbbbbbbbbbbbbbbbb"] \

end{tikzcd}

end{equation*}



end{document}