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math.FA2019
Sufficient criteria and sharp geometric conditions for observability in Banach spaces
Dennis Gallaun, Christian Seifert, Martin Tautenhahn
Let be Banach spaces, a -semigroup on , the corresponding infinitesimal generator on , a bounded linear operator from to , and $…
math.FA2019
On the harmonic extension approach to fractional powers in Banach spaces
Jan Meichsner, Christian Seifert
We show that fractional powers of general sectorial operators on Banach spaces can be obtained by the harmonic extension approach. Moreover, for the corresponding second order ordi…