I want to write a commutative diagram with tikz where some arrows are labeled with matrices. How can I improve the diagram to look correct, because the matrices look not correct in the diagram? Here is my work. and I want to do as in the picture.

b \arrow[r, "{\begin{pmatrix} \mu \\ -\pi \end{pmatrix}}"] \arrow[equal]{d} & c\oplus d \arrow[r, "{\begin{pmatrix} \rho &  \sigma \end{pmatrix}}"] \arrow[equal]{d} & e \arrow[r, "\lambda \nu"] \arrow[d, "\Phi"] & {b[1]} \arrow[equal]{d} \\
b \arrow[r, "{\begin{pmatrix} \mu \\ -\pi \end{pmatrix}}"']          & c\oplus d \arrow[r, "{\begin{pmatrix} \rho &  \sigma^\prime \end{pmatrix}}"']   & e \arrow[r, "\lambda \nu"']                  & {b[1]}          

enter image description here

I keep getting the following logs: undefined control sequences. Please can someone tell me what is wrong with my code?

  • 1
    Welcome! Please post a minimal, complete example that we can compile. See minimal working example (MWE)
    – Rmano
    Feb 13 at 11:51
  • 1
    you have posted an identical question here. Please try to create a viable example; re-posting the same does not help you nor us.
    – Rmano
    Feb 13 at 12:01
  • 1
    This question looks pretty much identical to your earlier question tex.stackexchange.com/q/633696/35864. Please do not ask the same question twice in short succession. Instead edit and improve your question following the comments you got. In particular consider turning the code snippet into a valid document (with \documentclass a preamble loading the required packages and \begin{document}...\end{document}).
    – moewe
    Feb 13 at 12:02
  • you have not even said what command was undefined, presumably you have loaded tikz-cd (although you do not show that) but pmatrix is not defined by default, when asking abiut a error always provide a file which reproduces the error and show the exact error message fron the log Feb 13 at 12:22


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