If $(e^{-tA})_{t>0}$ is a strongly continuous and contractive semigroup on a complex Banach space $B$, then $-(-A)^\alpha $, $0<\alpha <1$, generates a holomorphic semigroup on $B$. This was proved by K. Yosida in [7]. Using similar techniques, we present a class $H$ of Bernstein functions such that for all $f\in H$, the operator $-f(-A)$ generates a holomorphic semigroup.
@article{119334, author = {Adel Saddi}, title = {Holomorphic subordinated semigroups}, journal = {Commentationes Mathematicae Universitatis Carolinae}, volume = {43}, year = {2002}, pages = {457-466}, zbl = {1090.35109}, mrnumber = {1920520}, language = {en}, url = {http://dml.mathdoc.fr/item/119334} }
Saddi, Adel. Holomorphic subordinated semigroups. Commentationes Mathematicae Universitatis Carolinae, Tome 43 (2002) pp. 457-466. http://gdmltest.u-ga.fr/item/119334/
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