Natural annihilators and operators of constant rank over $\mathbb{C}$

Abstract

Even if the Fourier symbols of two constant rank differential operators have the same nullspace for each non-trivial phase space variable, the nullspaces of those differential operators might differ by an infinite-dimensional space. Under the natural condition of constant rank over $\mathbb{C}$, we establish that the equality of nullspaces on the Fourier symbol level already implies the equality of the nullspaces of the differential operators in ${\mathcal{D}}^{\prime }$ modulo polynomials of a fixed degree. In particular, this condition allows one to speak of natural annihilators within the framework of complexes of differential operators.