I am using the following code in my latex editor but is saying package ams error: old form '\matrix' should be \begin{matrix} \end{align}:

\mathscr{C} & \overset{F}{ \longrightarrow} & \mathscr{D} 
\cr  \downarrow  && \downarrow 
\cr \mathscr{C} \otimes A & \overset{{\color{red}{F \otimes 1}}}{\longrightarrow} & \mathscr{D} \otimes A}

enter image description here

But if remove \matrix{}, then it is perfectly running but in that case the figure is not perfect as above.

Any solution or package that solve the above problem ?

Please don'tsuggest Tikz-GD because it is not installed in MikTex in my folder

  • I got it. Using \begin{matrix}...\end{matrix}, the problem solved. But how to increase arrow sizes ?
    – learner
    Feb 2, 2021 at 13:10
  • 1
    Then why don't you just ask miktex to install tikz-cd for you? It is worth it.
    – daleif
    Feb 2, 2021 at 13:44
  • note it is tikz-cd and it is in miktex (and texlive) not Tikz-GD Feb 2, 2021 at 14:36

2 Answers 2


You could employ the amscd package, which is part of the amsmath bundle, to achieve your typesetting objective. See section 8, "Commutative diagrams", of the user guide of the amsmath package for a tutorial on this package.

enter image description here

\usepackage{amscd}    % for 'CD' ("commutative diagram") environment
\usepackage{mathrsfs} % for '\mathsrc' directive
\usepackage{xcolor}   % for '\textcolor' directive

\mathscr{C} @>F>> \mathscr{D} \\
@VVV @VVV \\
\mathscr{C}\otimes A @>\textcolor{red}{F\otimes1}>> \mathscr{D}\otimes A


Also with xy package you can obtained the same result of amscd package (they are similar).



\mathscr{C} \ar[d] \ar[r]^F & \mathscr{D} \ar[d] \\
\mathscr{C}\otimes A \ar[r]^{\color{red}{F\otimes 1}} & \mathscr{D}\otimes A }

enter image description here


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