Problem with error "Missing delimiter (.inserted)" with arrays

Question

I'm having some problems with this error and I don't know what to do. I have to use a certain template and it doesn't work anymore. Before it used to.

\documentclass[sn-mathphys]{sn-jnl}
\begin{document}
\begin{equation*}
\left.
  \begin{array}{l}
  \left.
  \begin{array}{l}
  \displaystyle{\vec{u}_{h,N}^{m}, \vec{u}_{h,N}^{m-1} \in W_{h}^{s}}\\
  W_{h}^{s}\,\,\mbox{vectorial space}
  \end{array}\right|
  \Rightarrow \displaystyle{\frac{\vec{u}_{h,N}^{m} - \vec{u}_{h,N}^{m-1}}{\tau/N} \in W_{h}^{s}}\\
  \left.
  \begin{array}{l}
  \displaystyle{\vec{\omega}_{h,N}^{m} \in {\cal W}_{h}}\\
  \displaystyle{\vec{\omega}_{h,N}^{m} = \vec{\omega}_{h,N}^{m}\vert_{\Omega_{s}}}
  \end{array}\right|
  \Rightarrow \vec{\omega}_{h,N}^{m} \in W_{h}^{s}\\
  \end{array}\right|
  \Rightarrow \vec{\theta}_{h,N}^{m} \in W_{h}^{s}
\end{equation*}
\end{document}

Welcome to TSE. Please post a Minimal Working Example, instead of a code snippet. — José Carlos Santos, Jul 24 '22 at 08:16
As I don't have you class installed, I replaced it with the report class and loaded amsmath. There was no problem with the compilation. — Bernard, Jul 24 '22 at 08:55

score 1 · Accepted Answer · answered Jul 24 '22 at 09:19

For very mysterious reasons the class loads the program package that serves essentially no purpose.

This has the nasty effect that | cannot be used as a delimiter.

Use \right\rvert instead.

On the other hand, you can improve your output.

\documentclass[sn-mathphys]{sn-jnl}
\begin{document}
\begin{equation}
% outer block
\left.
\begin{aligned}
  % top block
& \left.
  \begin{aligned}
    &\vec{u}{h,N}^{,m}, \vec{u}{h,N}^{,m-1} \in W_{h}^{s}
    \
    &W_{h}^{s}\text{ vector space}
  \end{aligned}
  \right\rvert
  \Rightarrow
  \frac{\vec{u}{h,N}^{,m} - \vec{u}{h,N}^{,m-1}}{\tau/N} \in W_{h}^{s}
\
  % bottom block
& \left.
  \begin{aligned}
    &\vec{\omega}{h,N}^{,m} \in \mathcal{W}{h}\
    &\vec{\omega}{h,N}^{,m} = \vec{\omega}{h,N}^{,m}\vert_{\Omega_{s}}
  \end{aligned}
  \right\rvert
  \Rightarrow
  \vec{\omega}{h,N}^{,m} \in W{h}^{s}
\end{aligned}
\right\rvert
\Rightarrow
\vec{\theta}{h,N}^{,m} \in W{h}^{s}
\end{equation}
\end{document}

Train yourself to use \, in the exponents to \vec{}

Also, the standard name in English is vector space (not vectorial); this is a common error for speakers of Italian or French.

Problem with error "Missing delimiter (.inserted)" with arrays

1 Answers1