Rapidly converging approximations and regularity theory

Abstract

We consider distributions on a closed compact manifold $M$ as maps on smoothing operators. Thus spaces of certain maps between ${\Psi }^{-\infty }(M)\to {\mathcal{C}}^{\infty }(M)$ are considered as generalized functions. For any collection of regularizing processes we produce an algebra of generalized functions and a diffeomorphism equivariant embedding of distributions into this algebra. We provide examples invariant under certain group actions. The regularity for such generalized functions is provided in terms of a certain tameness of maps between graded Frechét spaces. This notion of regularity implies the regularity in Colombeau algebras in the $\maG^{\infty}$ sense.

23 Pages