Csdrhrt

LaTeX complains Limit controls must follow a math operator. textbf{G} := parallellimits about the following snippet.

documentclass{article}



usepackage{mathtools}

begin{document}

    begin{equation}

        textbf{G} := parallellimits_{pi in mathcal{P}} textbf{G}^{pi} 

    end{equation}

end{document}

What is a possible workaround to apply limits to parallel?

Maybe you want a symbol similar to sum:

documentclass{article}



usepackage{mathtools,graphicx}



makeatletter

newcommand{parop}{DOTSBparop@slimits@}

newcommand{parop@}{mathop{vphantom{sum}mathpalettedelimiter@to@opVert}}

newcommand{delimiter@to@op}[2]{%

  begingroup

  sboxz@{$#1sum$}%

  vcenter{hbox{resizebox{!}{htz@}{$m@th#2$}}}%

  endgroup

}

makeatother



begin{document}



begin{equation}

textbf{G} coloneqq parop_{pi in mathcal{P}} textbf{G}^{pi} 

end{equation}



begin{equation}

sum_{pi in mathcal{P}} parop_{pi in mathcal{P}}

end{equation}



begin{equation}

textstyle sum_{pi in mathcal{P}} parop_{pi in mathcal{P}}

scriptstyle sum_{pi in mathcal{P}} parop_{pi in mathcal{P}}

scriptscriptstyle sum_{pi in mathcal{P}} parop_{pi in mathcal{P}}

end{equation}



end{document}

For a quick and dirty one-time-use solution, make it a math operator.

documentclass{article}



usepackage{mathtools}

begin{document}

    begin{equation}

        textbf{G} := mathop{parallel}limits_{pi in mathcal{P}} textbf{G}^{pi} 

    end{equation}

end{document}