Characterization of the domain of fractional powers of a class of elliptic differential operators with feedback boundary conditions (Q1358986)

I recommend the author's summary ``A class of elliptic differential operators with feedback boundary conditions of the Dirichlet type and the generalized Neumann type is studied. The domain of the fractional powers of these operators is completely characterized in terms of various Sobolev spaces. The results are an extension of the standard results of \textit{D. Fujiwara} [Proc. Japan Acad. 43, 426-428 (1967; Zbl 0182.42802)] and \textit{P. Grisvard} [Arch. Ratio. Mech. Anal. 25, 40-63 (1967; Zbl 0187.05901)]''.