Fourier transform for D-algebras, I

An analogue of the Fourier transform is developed for D-algebras. G. Laumon 's equivalence between the derived category of D-modules on an abelian vari ety and the derived category of G-modules on the universal extension of the dual variety is seen as a degenerate case of a duality for twisted differe ntial operators (tdo's) with respect to which the dual of a generic tdo is again a tdo.