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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…
math.FA2018
A note on perturbations of -semigroups
Christian Seifert, Hendrik Vogt, Marcus Waurick
This article deals with a variation of constants type inequality for semigroups acting consistently on a scale of Banach spaces. This inequality can be characterized by a correspon…