Solutions of the Schröder equation
Let E be a Frechet (resp. Frechet-Hilbert) space. It is shown that E ∈ (Ω) (resp. E ∈ (DN)) if and only if [H(OE)]' ∈ (Ω) (resp. [H(OE)]' ∈ (DN)). Moreover it is also shown that E ∈ (DN) if and only if Hb(E') ∈ (DN). In the nuclear case these results were proved by Meise and Vogt [2].