  **Case 0 :** $P_0 \sim_0$ [$S_{0,0}$]{}  Figure \[fig:pod0EQUIV0pod00\] shows the possible moves on $P_0$ or [$S_{0,0}$]{}, and the answer leading to a ${\mathcal{P}}$-position (for readability, we write $S$ instead of $\hat{S}$ in the figure).  (orig) at (0,0) [ ]{};  (remove