2015/09/28 by Santeri Miihkinen, Miihkinen, Santeri
Mathematics · #30H10 (Secondary ) #47G10 (Primary) #Advanced Banach Space Theory #Advanced Harmonic Analysis Research #FOS: Mathematics #Functional Analysis (math.FA) #Holomorphic and Operator Theory #math.FA #msc:30H10 #msc:47G10
paper · pdf · doi:10.48550/arxiv.1509.08356
14 pages, 1 figure
arxiv created 2015/09/28 · openalex publication_date 2015/09/28 · arxiv updated 2015/09/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
We prove that a Volterra-type integral operator Tgf(z) = ∫0z f(ζ)g'(ζ)dζ, z ∈ \mathbb D, defined on Hardy spaces Hp, 1 ≤ p < ∞, fixes an isomorphic copy of ℓp, if the operator Tg is not compact. In particular, this shows that the strict singularity of the operator Tg coincides with the compactness of the operator Tg on spaces Hp. As a consequence, we obtain a new proof for the equivalence of the compactness and the weak compactness of the operator Tg on H1.