Solution
= Solution
For constants $u=a-b$ and $D=(a+b)/2$, $z=x-ut$ removes drift and gives $\widetilde P_t=D\widetilde P_{zz}$.
= Solution
For constants $u=a-b$ and $D=(a+b)/2$, $z=x-ut$ removes drift and gives $\widetilde P_t=D\widetilde P_{zz}$.