<p>In this paper, we study the existence of isometries among the composition operators between several Banach spaces of analytic functions on the unit disk in <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="41980_2025_999_Article_IEq1.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="13" /> </InlineMediaObject> <EquationSource Format="TEX">\(\mathbb {C}\)</EquationSource> <EquationSource Format="MATHML"><math> <mi mathvariant="double-struck">C</mi> </math></EquationSource> </InlineEquation> with particular focus on the case when the domain and target spaces are different. We find that there are no composition isometries between several classical Banach spaces and prove that the only composition isometries on the derivative Hardy space <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="41980_2025_999_Article_IEq2.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="20" /> </InlineMediaObject> <EquationSource Format="TEX">\(S^p\)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi>S</mi> <mi>p</mi> </msup> </math></EquationSource> </InlineEquation> are induced by rotations. Finally, we show that none of the spaces <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="41980_2025_999_Article_IEq3.gif" Format="GIF" Height="18" Rendition="HTML" Resolution="72" Type="Linedraw" Width="20" /> </InlineMediaObject> <EquationSource Format="TEX">\(S^p_n\)</EquationSource> <EquationSource Format="MATHML"><math> <msubsup> <mi>S</mi> <mi>n</mi> <mi>p</mi> </msubsup> </math></EquationSource> </InlineEquation> consisting of the functions <i>f</i> whose <i>n</i>-th derivative is in the Hardy space <InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="41980_2025_999_Article_IEq4.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="24" /> </InlineMediaObject> <EquationSource Format="TEX">\(H^p\)</EquationSource> <EquationSource Format="MATHML"><math> <msup> <mi>H</mi> <mi>p</mi> </msup> </math></EquationSource> </InlineEquation> can support hypercyclic composition operators.</p>

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Isometries on Some Banach Spaces Among Composition Operators

  • Ebrahim Abbasi,
  • Flavia Colonna,
  • Mostafa Hassanlou

摘要

In this paper, we study the existence of isometries among the composition operators between several Banach spaces of analytic functions on the unit disk in \(\mathbb {C}\) C with particular focus on the case when the domain and target spaces are different. We find that there are no composition isometries between several classical Banach spaces and prove that the only composition isometries on the derivative Hardy space \(S^p\) S p are induced by rotations. Finally, we show that none of the spaces \(S^p_n\) S n p consisting of the functions f whose n-th derivative is in the Hardy space \(H^p\) H p can support hypercyclic composition operators.