$\left\{\begin{matrix}\\P=-1\text{; }P=0\text{, }&\text{unconditionally}\\P\in \mathrm{R}\text{, }&q=0\end{matrix}\right.$

$\left\{\begin{matrix}\\q=0\text{, }&\text{unconditionally}\\q\in \mathrm{R}\text{, }&P=-1\text{ or }P=0\end{matrix}\right.$