• Approximation numbers of composition operators on H^p spaces of Dirichlet series 

      Bayart, Frederic; Queffelec, Herve; Seip, Kristian (Journal article; Peer reviewed, 2016)
      By a theorem of the first named author, $\varphi $ generates a bounded composition operator on the Hardy space ${\mathscr{H}}^p$of Dirichlet series $(1\le p<\infty )$ only if $\varphi (s)=c_0 s+\psi (s)$, where $c_0$ is a ...
    • Decay rates for approximation numbers of composition operators 

      Queffelec, Herve; Seip, Kristian (Journal article; Peer reviewed, 2015)
      A general method for estimating the approximation numbers of composition operators on the Hardy space H 2, using finite-dimensional model subspaces, is studied and applied in the case when the symbol of the operator maps ...