Interpolated Subspaces of Exponential Vectors of the Unbounded Operators in Banach Spaces

Approximation spaces associated with Legendre differential operators

“…It follows that u ∈ E 4t 2 (D) and consequently u ∈ E(D). Using the inequality (4), (6), and the Paley-Wiener theorem, we obtain the quasi-norm equivalence…”

Tensor products of exponential type vectors of unbounded operators

“…For such operator the subspace of exponential type vectors coincides with the linear span of all its spectral subspaces. Some interpolation properties of spaces of exponential type vectors of the unbounded operators in Banach spaces are established in [1,2,3].…”