There, I had the opportunity to present my program in analysis. I explained how a manifold is the geometric counterpart of a commutative ring, and vector bundles are the counterpart of modules over that ring, and if you go to the non-commutative case you can treat linear and nonlinear differential equations. From this point of view, linear equations are defined to be D-modules, and if you write D in a more general form, you can consider nonlinear systems.