Title
Weak admissibility does not imply admissibility for analytic semigroups
Abstract
Two conjectures on admissible control operators by George Weiss are disproved in this paper. One conjecture says that an operator B defined on an infinite-dimensional Hilbert space U is an admissible control operator if for every element u∈U the vector Bu defines an admissible control operator. The other conjecture says that B is an admissible control operator if a certain resolvent estimate is satisfied. The examples given in this paper show that even for analytic semigroups the conjectures do not hold. In the last section we construct a semigroup example showing that the first estimate in the Hille–Yosida theorem is not sufficient to conclude boundedness of the semigroup.
Year
DOI
Venue
2003
10.1016/S0167-6911(02)00277-3
Systems & Control Letters
Keywords
Field
DocType
Infinite-dimensional system,Admissible control operator,Conditional basis,C0-semigroup
Hilbert space,Discrete mathematics,C0-semigroup,Resolvent,Operator (computer programming),Semigroup,Conjecture,Mathematics
Journal
Volume
Issue
ISSN
48
3
0167-6911
Citations 
PageRank 
References 
7
1.67
0
Authors
3
Name
Order
Citations
PageRank
Hans Zwart15310.37
Birgit Jacob272.01
Olof J. Staffans36615.08