Solution
= Solution
$D$ lowers total degree, so it is nilpotent and has only <eigenvalue> zero. Solving $(\partial_z+\partial_w)f=0$ gives $f=h(z-w)$; the degree restrictions give the eigenspace $\operatorname{span}\{1,z-w,(z-w)^2\}$.
= Solution
$D$ lowers total degree, so it is nilpotent and has only <eigenvalue> zero. Solving $(\partial_z+\partial_w)f=0$ gives $f=h(z-w)$; the degree restrictions give the eigenspace $\operatorname{span}\{1,z-w,(z-w)^2\}$.