Given the equation here, I would like to ask the following relaxed question:
Consider the PDE
$$\partial_t f(x,t) = \langle q(x), \nabla \rangle f(t,x) + p(x),$$
with Schwartz initial data $f(0,x) = f_0(x) \in \mathscr S(\mathbb R^n).$
I am wondering then if $q$ is Lipschitz and $p$ is Schwartz as $f_0$, does there exist a solution $(t,x)\mapsto f(t,x)$ for this equation that decays faster than any polynomial in the space variable $x$ for any fixed time $t>0$?