An Agler-type model theorem for C0-semigroups of Hilbert space contractions

Forskningsoutput: TidskriftsbidragArtikel i vetenskaplig tidskriftPeer review

4 Citeringar (SciVal)


We investigate suitable conditions for a C0-semigroup (T(t))t≥0 of Hilbert space contractions to be unitarily equivalent to the restriction of the adjoint shift semigroup (S∗γ(t))t≥0 to an invariant subspace of the standard weighted Bergman space Aγ−2(C+,K). It turns out that (T(t))t≥0 admits a model by (S∗γ(t))t≥0 if and only if its cogenerator is γ-hypercontractive and limt→0T(t)=0 in strong operator topology. We then discuss how such semigroups can be characterized without involving the cogenerator. A sufficient condition is that, for each t>0, the operator T(t) is γ-hypercontractive. Surprisingly, this condition is necessary if and only if γ is integer. The paper is concluded with a conjecture that would imply a more symmetric characterization.
Sidor (från-till)420-438
Antal sidor19
TidskriftJournal of the London Mathematical Society
StatusPublished - 2016 apr

Ämnesklassifikation (UKÄ)

  • Matematisk analys


Utforska forskningsämnen för ”An Agler-type model theorem for <em style="margin: 0px; padding: 0px; border: 0px; outline-style: none; font-size: inherit; font-family: inherit; line-height: inherit; text-align: inherit; vertical-align: baseline;">C</em><sub style="margin: 0px; padding: 0px; border: 0px; outline-style: none; font-style: inherit; font-size: 0.85em; font-family: inherit; line-height: 0; text-align: inherit;">0</sub>-semigroups of Hilbert space contractions”. Tillsammans bildar de ett unikt fingeravtryck.

Citera det här