# How I solve the problem of writing an formula with just one accolade?

I should write the following formula: This is the code:

\begin{equation}
Q_{sp}=\left\{\stackrel{\frac{\kappa_{0}\kappa_{1}\dots \kappa_{Zp-1}}{\mu_{1}\mu_{2}\dots\mu_{Zp} (1+\sum^{n}_{l=1} \frac{\kappa_{0}\kappa_{1}
\dots \kappa_{l-1}}{\mu_{1}\mu_{2}\dots \mu_{l}})} \dots 1\leq Zp\leq number\_pol}{\frac{1}{1+\sum^{n}_{l=1}\frac{\kappa_{0}\kappa_{1}
\dots \kappa_{l-1}}{\mu_{1}\mu_{2}\dots \mu_{l}}} \dots Zp=0}
\end{equation}


How I solve the problem of writing it by just one accolade without having this mistake

!Missing  \right. inserted

• you should add \right. immediately after the last line of the stack. \left always has to be paired with \right, even if one of them is empty. (that's where the period after \right comes in.) – barbara beeton Feb 24 '17 at 19:23
• You should use the dcases environment from mathtools instead. – Bernard Feb 24 '17 at 19:27
• How can I use dcases environment? – M.amani Feb 24 '17 at 19:30
• @M.amani: I've posted a code. – Bernard Feb 24 '17 at 19:53

Example from the manual from AMSmath package page 8.

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{equation*}
\left.
\begin{aligned}
B’&=-\partial\times E,\\
E’&=\partial\times B - 4\pi j,
\end{aligned}
\right\}
\end{equation*}
\end{document} Solution with your equation:

\documentclass{article}
\usepackage{amsmath}
\begin{document}
\begin{equation}
Q_{sp}=\left\{\stackrel{\frac{\kappa_{0}\kappa_{1}\dots \kappa_{Zp-1}}{\mu_{1}\mu_{2}\dots\mu_{Zp} (1+\sum^{n}_{l=1} \frac{\kappa_{0}\kappa_{1}\dots \kappa_{l-1}}{\mu_{1}\mu_{2}\dots \mu_{l}})} \dots 1\leq Zp\leq number\_pol}{\frac{1}{1+\sum^{n}_{l=1}\frac{\kappa_{0}\kappa_{1} \dots \kappa_{l-1}}{\mu_{1}\mu_{2}\dots \mu_{l}}} \dots Zp=0}\right.
\end{equation}
\end{document} Here is a solution with dcases, and some improvements for the vertical spacing:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{lmodern}
\usepackage{mathtools}

\begin{document}

\begin{equation}
Q_{sp}=\begin{dcases}\stackrel{\frac{\kappa_{0}\kappa_{1} ... \kappa_{Zp-1}}{\mu_{1}\mu_{2} ... \mu_{Zp} \bigl(1+\sum^n_{l=1} \frac{\kappa_{0}\kappa_{1}
\dotsm \kappa_{l-1}\mathstrut}{\mu_{1}\mu_{2} ... \mu_{l}}\bigr)} ... 1\leq Zp\leq \text{number\_pol}}{\frac{\strut1}{1+\sum^n_{l=1}\frac{\kappa_{0}\kappa_{1}
... \kappa_{l-1}}{\mu_{1}\mu_{2} ... \mu_{l}}} ... Zp=0}
\end{dcases}
\end{equation}

\end{document} 