<p>In this paper, we obtain Bohr-type inequalities for certain integral transforms, namely Fourier (discrete) and Laplace (discrete) transforms of bounded holomorphic functions <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="9_2025_2803_Article_IEq1.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="142" /> </InlineMediaObject> <EquationSource Format="TEX">\( f\in H^{\infty }\left( \Omega _{\gamma }, \mathcal {B} (\mathcal {H})\right) \)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>f</mi> <mo>∈</mo> <msup> <mi>H</mi> <mi>∞</mi> </msup> <mfenced close=")" open="("> <msub> <mi mathvariant="normal">Ω</mi> <mi>γ</mi> </msub> <mo>,</mo> <mi mathvariant="script">B</mi> <mrow> <mo stretchy="false">(</mo> <mi mathvariant="script">H</mi> <mo stretchy="false">)</mo> </mrow> </mfenced> </mrow> </math></EquationSource> </InlineEquation> be given by <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="9_2025_2803_Article_IEq2.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="136" /> </InlineMediaObject> <EquationSource Format="TEX">\( f(z)=\sum _{n=0}^{\infty }A_nz^n \)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>f</mi> <mrow> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mo>=</mo> <msubsup> <mo>∑</mo> <mrow> <mi>n</mi> <mo>=</mo> <mn>0</mn> </mrow> <mi>∞</mi> </msubsup> <msub> <mi>A</mi> <mi>n</mi> </msub> <msup> <mi>z</mi> <mi>n</mi> </msup> </mrow> </math></EquationSource> </InlineEquation> in <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="9_2025_2803_Article_IEq3.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="13" /> </InlineMediaObject> <EquationSource Format="TEX">\( \mathbb {D} \)</EquationSource> <EquationSource Format="MATHML"><math> <mi mathvariant="double-struck">D</mi> </math></EquationSource> </InlineEquation> with <InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="9_2025_2803_Article_IEq4.gif" Format="GIF" Height="26" Rendition="HTML" Resolution="72" Type="Linedraw" Width="168" /> </InlineMediaObject> <EquationSource Format="TEX">\(||f(z)||_{H^{\infty }\left( \Omega _{\gamma }, \mathcal {B} (\mathcal {H})\right) }\le 1,\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mrow> <mo stretchy="false">|</mo> <mo stretchy="false">|</mo> <mi>f</mi> <mrow> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mo stretchy="false">|</mo> <mo stretchy="false">|</mo> </mrow> <mrow> <msup> <mi>H</mi> <mi>∞</mi> </msup> <mfenced close=")" open="("> <msub> <mi mathvariant="normal">Ω</mi> <mi>γ</mi> </msub> <mo>,</mo> <mi mathvariant="script">B</mi> <mrow> <mo stretchy="false">(</mo> <mi mathvariant="script">H</mi> <mo stretchy="false">)</mo> </mrow> </mfenced> </mrow> </msub> <mo>≤</mo> <mn>1</mn> <mo>,</mo> </mrow> </math></EquationSource> </InlineEquation> where <InlineEquation ID="IEq5"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="9_2025_2803_Article_IEq5.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="82" /> </InlineMediaObject> <EquationSource Format="TEX">\(A_n\in \mathcal {B} (\mathcal {H})\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mi>A</mi> <mi>n</mi> </msub> <mo>∈</mo> <mi mathvariant="script">B</mi> <mrow> <mo stretchy="false">(</mo> <mi mathvariant="script">H</mi> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> for <InlineEquation ID="IEq6"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="9_2025_2803_Article_IEq6.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="136" /> </InlineMediaObject> <EquationSource Format="TEX">\(n\in \mathbb {N}_0:=\mathbb {N}\cup \{0\}\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>n</mi> <mo>∈</mo> <msub> <mi mathvariant="double-struck">N</mi> <mn>0</mn> </msub> <mo>:</mo> <mo>=</mo> <mi mathvariant="double-struck">N</mi> <mo>∪</mo> <mrow> <mo stretchy="false">{</mo> <mn>0</mn> <mo stretchy="false">}</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> and <InlineEquation ID="IEq7"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="9_2025_2803_Article_IEq7.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="77" /> </InlineMediaObject> <EquationSource Format="TEX">\(||A_0||&lt;1,\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mrow> <mo stretchy="false">|</mo> <mo stretchy="false">|</mo> </mrow> <msub> <mi>A</mi> <mn>0</mn> </msub> <mrow> <mo stretchy="false">|</mo> <mo stretchy="false">|</mo> </mrow> <mo>&lt;</mo> <mn>1</mn> <mo>,</mo> </mrow> </math></EquationSource> </InlineEquation> and <Equation ID="Equ24"> <MediaObject> <ImageObject Color="BlackWhite" FileRef="9_2025_2803_Article_Equ24.gif" Format="GIF" Height="43" Rendition="HTML" Resolution="72" Type="Linedraw" Width="387" /> </MediaObject> <EquationSource Format="TEX">\(\begin{aligned} \Omega _\gamma :=\biggl \{z\in \mathbb {C}: \bigg |z+\dfrac{\gamma }{1-\gamma }\bigg |&lt;\dfrac{1}{1-\gamma }\;\text{ for }\; 0\le \gamma &lt;1\biggr \}. \end{aligned}\)</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mrow> <mtable> <mtr> <mtd columnalign="right"> <mrow> <msub> <mi mathvariant="normal">Ω</mi> <mi>γ</mi> </msub> <mo>:</mo> <mo>=</mo> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">{</mo> </mrow> <mi>z</mi> <mo>∈</mo> <mi mathvariant="double-struck">C</mi> <mo>:</mo> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">|</mo> </mrow> <mi>z</mi> <mo>+</mo> <mstyle displaystyle="true" scriptlevel="0"> <mfrac> <mi>γ</mi> <mrow> <mn>1</mn> <mo>-</mo> <mi>γ</mi> </mrow> </mfrac> </mstyle> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">|</mo> </mrow> <mo>&lt;</mo> <mstyle displaystyle="true" scriptlevel="0"> <mfrac> <mn>1</mn> <mrow> <mn>1</mn> <mo>-</mo> <mi>γ</mi> </mrow> </mfrac> </mstyle> <mspace width="0.277778em" /> <mspace width="0.333333em" /> <mtext>for</mtext> <mspace width="0.333333em" /> <mspace width="0.277778em" /> <mn>0</mn> <mo>≤</mo> <mi>γ</mi> <mo>&lt;</mo> <mn>1</mn> <mrow> <mo maxsize="2.047em" minsize="2.047em" stretchy="true">}</mo> </mrow> <mo>.</mo> </mrow> </mtd> </mtr> </mtable> </mrow> </math></EquationSource> </Equation>Moreover, we establish the Bohr–Rogosinski inequality for Cesáro operator on the class <InlineEquation ID="IEq8"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="9_2025_2803_Article_IEq8.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="102" /> </InlineMediaObject> <EquationSource Format="TEX">\( H^{\infty }\left( \mathbb {D}, \mathcal {B} (\mathcal {H})\right) \)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msup> <mi>H</mi> <mi>∞</mi> </msup> <mfenced close=")" open="("> <mi mathvariant="double-struck">D</mi> <mo>,</mo> <mi mathvariant="script">B</mi> <mo stretchy="false">(</mo> <mi mathvariant="script">H</mi> <mo stretchy="false">)</mo> </mfenced> </mrow> </math></EquationSource> </InlineEquation> of holomorphic functions <i>f</i>. All the results are proved to be sharp.</p>

错误:搜索内容不能为空,请输入英文关键词
错误:关键词超出字数限制,请精简
高级检索

Operator Valued Bohr-Type Inequalities for Certain Integral Transforms

  • Sabir Ahammed,
  • Molla Basir Ahamed

摘要

In this paper, we obtain Bohr-type inequalities for certain integral transforms, namely Fourier (discrete) and Laplace (discrete) transforms of bounded holomorphic functions \( f\in H^{\infty }\left( \Omega _{\gamma }, \mathcal {B} (\mathcal {H})\right) \) f H Ω γ , B ( H ) be given by \( f(z)=\sum _{n=0}^{\infty }A_nz^n \) f ( z ) = n = 0 A n z n in \( \mathbb {D} \) D with \(||f(z)||_{H^{\infty }\left( \Omega _{\gamma }, \mathcal {B} (\mathcal {H})\right) }\le 1,\) | | f ( z ) | | H Ω γ , B ( H ) 1 , where \(A_n\in \mathcal {B} (\mathcal {H})\) A n B ( H ) for \(n\in \mathbb {N}_0:=\mathbb {N}\cup \{0\}\) n N 0 : = N { 0 } and \(||A_0||<1,\) | | A 0 | | < 1 , and \(\begin{aligned} \Omega _\gamma :=\biggl \{z\in \mathbb {C}: \bigg |z+\dfrac{\gamma }{1-\gamma }\bigg |<\dfrac{1}{1-\gamma }\;\text{ for }\; 0\le \gamma <1\biggr \}. \end{aligned}\) Ω γ : = { z C : | z + γ 1 - γ | < 1 1 - γ for 0 γ < 1 } . Moreover, we establish the Bohr–Rogosinski inequality for Cesáro operator on the class \( H^{\infty }\left( \mathbb {D}, \mathcal {B} (\mathcal {H})\right) \) H D , B ( H ) of holomorphic functions f. All the results are proved to be sharp.