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Functional Calculus for operators and semigroups under resolvent or boundedness conditions

Objective

It is planned to obtain some estimates of a functional calculus (defined in terms of the Lap lace transform) for semi groups. To this aim the duality method successfully used by the applicant for the single operator case (with the spectrum in the unit disc) shall be applied. Most interesting is the case of bounded semi groups and semi groups whose generators (with the spectrum in the left half plane) satisfy some resolving growth conditions (analogues of Kris and Tadmor-Ritt conditions for a single operator). In particular, in the case of entire functions of a given exponential type (which are analogues of the polynomials of a given degree), one can hope to obtain some estimates in terms of the type. Some intermediate stages will consist in finding a half plane version of the notions and theorems that have been used in the case of a single operator: the Besot classes and the spaces of Cauchy-Stieltjes integrals and their multipliers, the Rises turndown collar theorem on the uniform convergence of power series, etc. It is intended to study the sharpness of the estimates obtained in the case of semi groups, and also in the single operator case where the question remains unanswered (i.e. for operators on Hilbert spaces). This, probably, could be done with the help of the functional model and Foguel-Hankel operators. Applications to evolution equations shall be elaborated.

Call for proposal

FP6-2002-MOBILITY-5
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Coordinator

UNIVERSITAET ULM
EU contribution
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Address
Albert-Einstein-Allee 45
ULM
Germany

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Total cost
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