Command \eqref just shows the name of the equation (SBmetamodel) instead of the equation number (which is shown next to the equation), and I get the error: "Undefined control sequence. ...as shown in \eqref{SBmetamodel}". I'm compiling with pdfLaTeX (and Biber when adding new references with biblatex). I have checked multiple questions regarding \eqref not working, but I did not find any of the mentioned mistakes in my code.

\documentclass[a4paper, 11pt, onecolumn]{article}

... as shown in \eqref{SBmetamodel}.
\begin{equation} \label{SBmetamodel} 
y=\beta_{0} + \sum_{j=1}^{k} \beta_{j} x_{j} + \sum_{j=1}^{k-1} \sum_{j'=j+1}^{k} \beta_{j;j'} x_{j} x_{j'} + \sum_{j=1}^{k} \beta_{j;j} x_{j}^{2} + e    
\end {equation}

  • eqref needs the amsmath package. Jul 18, 2022 at 10:32

1 Answer 1


You first minimize your example, to see that biblatex is not involved and neither is the complicated equation:



... as shown in \eqref{SBmetamodel}.
\begin{equation} \label{SBmetamodel}
\end {equation}


If you run LaTeX on this, you get

! Undefined control sequence.
l.5 ... as shown in \eqref

and this shows where the main issue is. If you hit return, TeX will ignore the undefined command and print “SBmetamodel”, because it has no idea that this part has to be somehow processed. If you instead hit h followed by return, you get

The control sequence at the end of the top line
of your error message was never \def'ed. If you have
misspelled it (e.g., `\hobx'), type `I' and the correct
spelling (e.g., `I\hbox'). Otherwise just continue,
and I'll forget about whatever was undefined.

So the problem is that \eqref is not recognized. Why? Because it's a command defined by amsmath. Add


and you'll have your equation reference (after a couple of runs), besides several tools for math typesetting.

Never ignore errors during a LaTeX run.

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