On basis structure of power Köthe spaces of the first type

It is proved that Montel power Köthe spaces of the first type [5,8] have the structure of basis subspaces of the finite or infinite type invariant under isomorphisms, which strengthens authors’ previous results (joint with T. Terzioğlu) [18,19]. The main tools are special compound linear topological invariants, which evaluate classical geometric characteristic (namely inverse Bernstein diameters) of certain invariant multi-parameter constructions built from given bases of neighborhoods or bounded sets.