<p>Let <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\(\mathscr {A}(\mathbb {U})\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="script">A</mi> <mo stretchy="false">(</mo> <mi mathvariant="double-struck">U</mi> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> denote the space of holomorphic functions on the unit disc <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\mathbb {U}\)</EquationSource> <EquationSource Format="MATHML"><math> <mi mathvariant="double-struck">U</mi> </math></EquationSource> </InlineEquation>, and let <InlineEquation ID="IEq3"> <EquationSource Format="TEX">\(\mathscr {S}(\mathbb {U})\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="script">S</mi> <mo stretchy="false">(</mo> <mi mathvariant="double-struck">U</mi> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> be the family of analytic self-maps of <InlineEquation ID="IEq4"> <EquationSource Format="TEX">\(\mathbb {U}\)</EquationSource> <EquationSource Format="MATHML"><math> <mi mathvariant="double-struck">U</mi> </math></EquationSource> </InlineEquation>. Fix <InlineEquation ID="IEq5"> <EquationSource Format="TEX">\(n \in \mathbb {N}_0\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>n</mi> <mo>∈</mo> <msub> <mi mathvariant="double-struck">N</mi> <mn>0</mn> </msub> </mrow> </math></EquationSource> </InlineEquation> and consider analytic symbols <InlineEquation ID="IEq6"> <EquationSource Format="TEX">\(\varvec{\Phi }=(\phi _j)_{j=0}^n \subset \mathscr {A}(\mathbb {U})\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mrow> <mi mathvariant="bold">Φ</mi> </mrow> <mo>=</mo> <msubsup> <mrow> <mo stretchy="false">(</mo> <msub> <mi>ϕ</mi> <mi>j</mi> </msub> <mo stretchy="false">)</mo> </mrow> <mrow> <mi>j</mi> <mo>=</mo> <mn>0</mn> </mrow> <mi>n</mi> </msubsup> <mo>⊂</mo> <mi mathvariant="script">A</mi> <mrow> <mo stretchy="false">(</mo> <mi mathvariant="double-struck">U</mi> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> together with a composition symbol <InlineEquation ID="IEq7"> <EquationSource Format="TEX">\(\sigma \in \mathscr {S}(\mathbb {U})\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>σ</mi> <mo>∈</mo> <mi mathvariant="script">S</mi> <mo stretchy="false">(</mo> <mi mathvariant="double-struck">U</mi> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation>. This paper investigates the sum-type operator <Equation ID="Equ20"> <EquationSource Format="TEX">\( \mathcal {T}_{\varvec{\Phi },\sigma }^{\,n} h(u) = \sum _{j=0}^n \phi _j(u)\, h^{(j)}(\sigma (u)), \qquad h \in \mathscr {A}(\mathbb {U}), \)</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mrow> <msubsup> <mi mathvariant="script">T</mi> <mrow> <mrow> <mi mathvariant="bold">Φ</mi> </mrow> <mo>,</mo> <mi>σ</mi> </mrow> <mrow> <mspace width="0.166667em" /> <mi>n</mi> </mrow> </msubsup> <mi>h</mi> <mrow> <mo stretchy="false">(</mo> <mi>u</mi> <mo stretchy="false">)</mo> </mrow> <mo>=</mo> <munderover> <mo>∑</mo> <mrow> <mi>j</mi> <mo>=</mo> <mn>0</mn> </mrow> <mi>n</mi> </munderover> <msub> <mi>ϕ</mi> <mi>j</mi> </msub> <mrow> <mo stretchy="false">(</mo> <mi>u</mi> <mo stretchy="false">)</mo> </mrow> <mspace width="0.166667em" /> <msup> <mi>h</mi> <mrow> <mo stretchy="false">(</mo> <mi>j</mi> <mo stretchy="false">)</mo> </mrow> </msup> <mrow> <mo stretchy="false">(</mo> <mi>σ</mi> <mrow> <mo stretchy="false">(</mo> <mi>u</mi> <mo stretchy="false">)</mo> </mrow> <mo stretchy="false">)</mo> </mrow> <mo>,</mo> <mspace width="2em" /> <mi>h</mi> <mo>∈</mo> <mi mathvariant="script">A</mi> <mrow> <mo stretchy="false">(</mo> <mi mathvariant="double-struck">U</mi> <mo stretchy="false">)</mo> </mrow> <mo>,</mo> </mrow> </math></EquationSource> </Equation>and derives necessary and sufficient conditions for its boundedness and compactness when acting from a Banach space <InlineEquation ID="IEq8"> <EquationSource Format="TEX">\(\mathcal {X} \subset \mathscr {A}(\mathbb {U})\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="script">X</mi> <mo>⊂</mo> <mi mathvariant="script">A</mi> <mo stretchy="false">(</mo> <mi mathvariant="double-struck">U</mi> <mo stretchy="false">)</mo> </mrow> </math></EquationSource> </InlineEquation> into the weighted Zygmund-type spaces <InlineEquation ID="IEq9"> <EquationSource Format="TEX">\(\mathfrak {Z}_{\omega }\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi mathvariant="fraktur">Z</mi> <mi>ω</mi> </msub> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq10"> <EquationSource Format="TEX">\(\mathfrak {Z}_{\omega ,0}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi mathvariant="fraktur">Z</mi> <mrow> <mi>ω</mi> <mo>,</mo> <mn>0</mn> </mrow> </msub> </math></EquationSource> </InlineEquation> and the weighted Bloch-type spaces <InlineEquation ID="IEq11"> <EquationSource Format="TEX">\(\mathfrak {B}_{\omega }\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi mathvariant="fraktur">B</mi> <mi>ω</mi> </msub> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq12"> <EquationSource Format="TEX">\(\mathfrak {B}_{\omega ,0}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi mathvariant="fraktur">B</mi> <mrow> <mi>ω</mi> <mo>,</mo> <mn>0</mn> </mrow> </msub> </math></EquationSource> </InlineEquation>. These conditions are formulated in terms of weighted supremum estimates involving <InlineEquation ID="IEq13"> <EquationSource Format="TEX">\(\varvec{\Phi }\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="bold">Φ</mi> </mrow> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq14"> <EquationSource Format="TEX">\(\sigma \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>σ</mi> </math></EquationSource> </InlineEquation>, and their derivatives, under minimal structural assumptions on <InlineEquation ID="IEq15"> <EquationSource Format="TEX">\(\mathcal {X}\)</EquationSource> <EquationSource Format="MATHML"><math> <mi mathvariant="script">X</mi> </math></EquationSource> </InlineEquation> and the weight <InlineEquation ID="IEq16"> <EquationSource Format="TEX">\(\omega \)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ω</mi> </math></EquationSource> </InlineEquation>. The results reveal how the boundary behavior of the inducing symbols determines the transition between boundedness and compactness.</p>

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Sum–type differentiation–composition operators from a large class of analytic function spaces to weighted Zygmund–type spaces

  • Mohammed Said Al Ghafri

摘要

Let \(\mathscr {A}(\mathbb {U})\) A ( U ) denote the space of holomorphic functions on the unit disc \(\mathbb {U}\) U , and let \(\mathscr {S}(\mathbb {U})\) S ( U ) be the family of analytic self-maps of \(\mathbb {U}\) U . Fix \(n \in \mathbb {N}_0\) n N 0 and consider analytic symbols \(\varvec{\Phi }=(\phi _j)_{j=0}^n \subset \mathscr {A}(\mathbb {U})\) Φ = ( ϕ j ) j = 0 n A ( U ) together with a composition symbol \(\sigma \in \mathscr {S}(\mathbb {U})\) σ S ( U ) . This paper investigates the sum-type operator \( \mathcal {T}_{\varvec{\Phi },\sigma }^{\,n} h(u) = \sum _{j=0}^n \phi _j(u)\, h^{(j)}(\sigma (u)), \qquad h \in \mathscr {A}(\mathbb {U}), \) T Φ , σ n h ( u ) = j = 0 n ϕ j ( u ) h ( j ) ( σ ( u ) ) , h A ( U ) , and derives necessary and sufficient conditions for its boundedness and compactness when acting from a Banach space \(\mathcal {X} \subset \mathscr {A}(\mathbb {U})\) X A ( U ) into the weighted Zygmund-type spaces \(\mathfrak {Z}_{\omega }\) Z ω , \(\mathfrak {Z}_{\omega ,0}\) Z ω , 0 and the weighted Bloch-type spaces \(\mathfrak {B}_{\omega }\) B ω , \(\mathfrak {B}_{\omega ,0}\) B ω , 0 . These conditions are formulated in terms of weighted supremum estimates involving \(\varvec{\Phi }\) Φ , \(\sigma \) σ , and their derivatives, under minimal structural assumptions on \(\mathcal {X}\) X and the weight \(\omega \) ω . The results reveal how the boundary behavior of the inducing symbols determines the transition between boundedness and compactness.