SIAM Journal on Control and Optimization, Vol.48, No.4, 2620-2635, 2009
COUNTEREXAMPLES TO THE DISCRETE AND CONTINUOUS WEIGHTED WEISS CONJECTURES
Counterexamples are presented to weighted forms of the Weiss conjecture in discrete and continuous time. In particular, for certain ranges of a, operators are constructed that satisfy a given resolvent estimate, but fail to be delta-admissible. For alpha is an element of (-1, 0) the operators constructed are normal, while for alpha is an element of (0, 1) the operator is the unilateral shift on the Hardy space H(2)(D).