The Radon–Penrose Correspondence II: Line Bundles and Simple D-Modules

On a complex manifoldXof dimension ⩾3, we show that coherent DX-modules which are “simple” all overP*Xare classified by Pic(X), the family of holomorphic line bundles onX. As a corollary, using the Penrose transform, we obtain that on the complex Minkowski space M, simple DM-modules along the characteristic variety of the wave equation are classified by (half) integers, the so-called helicity.