Interpolation with a function parameter and refined scale of spaces

The interpolation of couples of separable Hilbert spaces with a function parameter is studied. The main properties of the classic interpolation are proved. Some applications to the interpolation of isotropic Hormander spaces over a closed manifold are given.

Elliptic systems of pseudodifferential equations in a refined scale on a closed manifold

We study a system of pseudodifferential equations that is elliptic in the sense of Petrovskii on a closed compact smooth manifold. We prove that the operator generated by the system is Fredholm one on a refined two-sided scale of the functional Hilbert spaces. Elements of this scale are the special isotropic spaces of H{o}rmander--Volevich--Paneah.