Remark: A relation outside the wave family; sign check

With $\eta =\mathrm{diag}(1,-1,-1,-1)$, ${\partial }_{0}Q=2z_0$ and ${\partial }_{1}Q=-2z_1$, so $p_{e_0}=-2z_0$, $p_{e_1}=2z_1$, $p_{e_0}{p}_{e_1}=-4z_0{z}_1$, and $p_{e_0+e_1}=-8z_0{z}_1$. Hence $({\partial }_{0}S)({\partial }_{1}S)=\frac{1}{2}S{\partial }_0{\partial }_{1}S$ on $\Omega$ (Theorem thm:wpA-Sbv); this is the relation q{1, 0} - (1/2) q{(), 01} = 0. The script checks exactly this example (require: “sign example”). The relation is not generated by $\square S=0$.