ArticleOriginal scientific textNorm continuity of
Title
Norm continuity of -semigroups
Authors 1, 1
Affiliations
- Mathematisches Institut I, Universität Karlsruhe, Englerstr. 2, D-76128 Karlsruhe, Germany
Abstract
We show that a positive semigroup on with generator A and ||R(α + i β)|| → 0 as |β| → ∞ for some α ∈ ℝ is continuous in the operator norm for t>0. The proof is based on a criterion for norm continuity in terms of "smoothing properties" of certain convolution operators on general Banach spaces and an extrapolation result for the -scale, which may be of independent interest.
Bibliography
- H. Alt, Lineare Funktionalanalysis, Springer, Berlin, 1992.
- J. Bergh and J. Löfström, Interpolation Spaces, Springer, Berlin, 1976.
- E. B. Davies, One-Parameter Semigroups, Academic Press, London, 1980.
- A. Driouich and O. El-Mennaoui, On the inverse formula of Laplace transforms, preprint.
- O. El-Mennaoui and K. J. Engel, On the characterization of eventually norm continuous semigroups in Hilbert space. Arc. Math. (Basel) 63 (1994), 437-440.
- O. El-Mennaoui and K. J. Engel, Towards a characterization of eventually norm continuous semigroups on Banach spaces, Quaestiones Math. 19 (1996), 183-190.
- J. Martinez and J. Mazon,
-semigroups norm continuous at infinity, Semigroup Forum 52 (1996), 213-224. - J. van Neerven, The Asymptotic Behaviour of Semigroups of Linear Operators, Birkhäuser, Basel, 1996.
- A. Pazy, Semigroups of Linear Operators and Applications to Partial Differential Equations, Springer, New York, 1983.
- L. Weis, A short proof for the stability theorem for positive semigroups on
, Proc. Amer. Math. Soc. (1998), to appear. - L. Weis, Integral operators and changes of density, Indiana Univ. Math. J. 31 (1982), 83-96.
- P. You, Characteristic conditions for
-semigroups with continuity in the uniform operator topology for t>0, Proc. Amer. Math. Soc. 116 (1992), 991-997.