<p>Let <i>P</i>(<i>z</i>) be a polynomial of degree at most <i>n</i>, and <InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10958_2025_7956_Article_IEq1.gif" Format="GIF" Height="22" Rendition="HTML" Resolution="72" Type="Linedraw" Width="252" /> </InlineMediaObject> <EquationSource Format="TEX">\(\tilde{\mathbb {S}}_a[P(z)]= (1+az)P'(z)-naP(z)\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mover accent="true"> <mi mathvariant="double-struck">S</mi> <mo stretchy="false">~</mo> </mover> <mi>a</mi> </msub> <mrow> <mo stretchy="false">[</mo> <mi>P</mi> <mrow> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mo stretchy="false">]</mo> </mrow> <mo>=</mo> <mrow> <mo stretchy="false">(</mo> <mn>1</mn> <mo>+</mo> <mi>a</mi> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <msup> <mi>P</mi> <mo>′</mo> </msup> <mrow> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mo>-</mo> <mi>n</mi> <mi>a</mi> <mi>P</mi> <mrow> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation>, and denote the modified Smirnov operator, where <i>a</i> is a real or complex number in <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10958_2025_7956_Article_IEq2.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="52" /> </InlineMediaObject> <EquationSource Format="TEX">\(|z| \le 1\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mo stretchy="false">|</mo> <mi>z</mi> <mo stretchy="false">|</mo> <mo>≤</mo> <mn>1</mn> </mrow> </math></EquationSource> </InlineEquation>. In this paper, we consider the operators <i>B</i> and <InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10958_2025_7956_Article_IEq3.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="19" /> </InlineMediaObject> <EquationSource Format="TEX">\(\tilde{\mathbb {S}}_a\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mover accent="true"> <mi mathvariant="double-struck">S</mi> <mo stretchy="false">~</mo> </mover> <mi>a</mi> </msub> </math></EquationSource> </InlineEquation> such that operator <i>B</i> carries <InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10958_2025_7956_Article_IEq4.gif" Format="GIF" Height="22" Rendition="HTML" Resolution="72" Type="Linedraw" Width="61" /> </InlineMediaObject> <EquationSource Format="TEX">\(\tilde{\mathbb {S}}_a[P(z)]\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <msub> <mover accent="true"> <mi mathvariant="double-struck">S</mi> <mo stretchy="false">~</mo> </mover> <mi>a</mi> </msub> <mrow> <mo stretchy="false">[</mo> <mi>P</mi> <mrow> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mo stretchy="false">]</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> into <Equation ID="Equ39"> <MediaObject> <ImageObject Color="BlackWhite" FileRef="10958_2025_7956_Article_Equ39.gif" Format="GIF" Height="41" Rendition="HTML" Resolution="72" Type="Linedraw" Width="474" /> </MediaObject> <EquationSource Format="TEX">\(\begin{aligned} B[\tilde{\mathbb {S}}_a[P(z)]] = \lambda _0\tilde{\mathbb {S}}_a[P(z)] + \lambda _1 \frac{mz}{2}\tilde{\mathbb {S}}_a[P'(z)] + \lambda _2\left( \frac{mz}{2}\right) ^2\frac{\tilde{\mathbb {S}}_a[P''(z)]}{2!}, \end{aligned}\)</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mrow> <mtable> <mtr> <mtd columnalign="right"> <mrow> <mi>B</mi> <mrow> <mo stretchy="false">[</mo> <msub> <mover accent="true"> <mi mathvariant="double-struck">S</mi> <mo stretchy="false">~</mo> </mover> <mi>a</mi> </msub> <mrow> <mo stretchy="false">[</mo> <mi>P</mi> <mrow> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mo stretchy="false">]</mo> </mrow> <mo stretchy="false">]</mo> </mrow> <mo>=</mo> <msub> <mi>λ</mi> <mn>0</mn> </msub> <msub> <mover accent="true"> <mi mathvariant="double-struck">S</mi> <mo stretchy="false">~</mo> </mover> <mi>a</mi> </msub> <mrow> <mo stretchy="false">[</mo> <mi>P</mi> <mrow> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mo stretchy="false">]</mo> </mrow> <mo>+</mo> <msub> <mi>λ</mi> <mn>1</mn> </msub> <mfrac> <mrow> <mi mathvariant="italic">mz</mi> </mrow> <mn>2</mn> </mfrac> <msub> <mover accent="true"> <mi mathvariant="double-struck">S</mi> <mo stretchy="false">~</mo> </mover> <mi>a</mi> </msub> <mrow> <mo stretchy="false">[</mo> <msup> <mi>P</mi> <mo>′</mo> </msup> <mrow> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mo stretchy="false">]</mo> </mrow> <mo>+</mo> <msub> <mi>λ</mi> <mn>2</mn> </msub> <msup> <mfenced close=")" open="("> <mfrac> <mrow> <mi mathvariant="italic">mz</mi> </mrow> <mn>2</mn> </mfrac> </mfenced> <mn>2</mn> </msup> <mfrac> <mrow> <msub> <mover accent="true"> <mi mathvariant="double-struck">S</mi> <mo stretchy="false">~</mo> </mover> <mi>a</mi> </msub> <mrow> <mo stretchy="false">[</mo> <msup> <mi>P</mi> <mrow> <mo>′</mo> <mo>′</mo> </mrow> </msup> <mrow> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mo stretchy="false">]</mo> </mrow> </mrow> <mrow> <mn>2</mn> <mo>!</mo> </mrow> </mfrac> <mo>,</mo> </mrow> </mtd> </mtr> </mtable> </mrow> </math></EquationSource> </Equation>where <InlineEquation ID="IEq5"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10958_2025_7956_Article_IEq5.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="156" /> </InlineMediaObject> <EquationSource Format="TEX">\(0\le m \le n-1, \lambda _0, \lambda _1\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mn>0</mn> <mo>≤</mo> <mi>m</mi> <mo>≤</mo> <mi>n</mi> <mo>-</mo> <mn>1</mn> <mo>,</mo> <msub> <mi>λ</mi> <mn>0</mn> </msub> <mo>,</mo> <msub> <mi>λ</mi> <mn>1</mn> </msub> </mrow> </math></EquationSource> </InlineEquation>, and <InlineEquation ID="IEq6"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10958_2025_7956_Article_IEq6.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">\( \lambda _2\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>λ</mi> <mn>2</mn> </msub> </math></EquationSource> </InlineEquation> are such that all the zeros of <Equation ID="Equ40"> <MediaObject> <ImageObject Color="BlackWhite" FileRef="10958_2025_7956_Article_Equ40.gif" Format="GIF" Height="43" Rendition="HTML" Resolution="72" Type="Linedraw" Width="277" /> </MediaObject> <EquationSource Format="TEX">\(\begin{aligned} u(z) = \lambda _0 + \left( {\begin{array}{c}m\\ 1\end{array}}\right) \lambda _1 z + \left( {\begin{array}{c}m\\ 2\end{array}}\right) \lambda _2 z^2, \end{aligned}\)</EquationSource> <EquationSource Format="MATHML"><math display="block"> <mrow> <mtable> <mtr> <mtd columnalign="right"> <mrow> <mi>u</mi> <mrow> <mo stretchy="false">(</mo> <mi>z</mi> <mo stretchy="false">)</mo> </mrow> <mo>=</mo> <msub> <mi>λ</mi> <mn>0</mn> </msub> <mo>+</mo> <mfenced close=")" open="("> <mrow> <mtable> <mtr> <mtd> <mi>m</mi> </mtd> </mtr> <mtr> <mtd> <mrow> <mrow /> <mn>1</mn> </mrow> </mtd> </mtr> </mtable> </mrow> </mfenced> <msub> <mi>λ</mi> <mn>1</mn> </msub> <mi>z</mi> <mo>+</mo> <mfenced close=")" open="("> <mrow> <mtable> <mtr> <mtd> <mi>m</mi> </mtd> </mtr> <mtr> <mtd> <mrow> <mrow /> <mn>2</mn> </mrow> </mtd> </mtr> </mtable> </mrow> </mfenced> <msub> <mi>λ</mi> <mn>2</mn> </msub> <msup> <mi>z</mi> <mn>2</mn> </msup> <mo>,</mo> </mrow> </mtd> </mtr> </mtable> </mrow> </math></EquationSource> </Equation>lie in the half-plane <InlineEquation ID="IEq7"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10958_2025_7956_Article_IEq7.gif" Format="GIF" Height="20" Rendition="HTML" Resolution="72" Type="Linedraw" Width="72" /> </InlineMediaObject> <EquationSource Format="TEX">\(Re \ z \le \frac{m}{4}\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>R</mi> <mi>e</mi> <mspace width="4pt" /> <mi>z</mi> <mo>≤</mo> <mfrac> <mi>m</mi> <mn>4</mn> </mfrac> </mrow> </math></EquationSource> </InlineEquation> and obtain some compact generalizations of some well-known polynomial inequalities.</p>

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AN OPERATOR PRESERVING INEQUALITIES BETWEEN A POLYNOMIAL AND ITS MODIFIED SMIRNOV OPERATOR

  • Deepak Kumar,
  • Dinesh Tripathi,
  • Sunil Hans

摘要

Let P(z) be a polynomial of degree at most n, and \(\tilde{\mathbb {S}}_a[P(z)]= (1+az)P'(z)-naP(z)\) S ~ a [ P ( z ) ] = ( 1 + a z ) P ( z ) - n a P ( z ) , and denote the modified Smirnov operator, where a is a real or complex number in \(|z| \le 1\) | z | 1 . In this paper, we consider the operators B and \(\tilde{\mathbb {S}}_a\) S ~ a such that operator B carries \(\tilde{\mathbb {S}}_a[P(z)]\) S ~ a [ P ( z ) ] into \(\begin{aligned} B[\tilde{\mathbb {S}}_a[P(z)]] = \lambda _0\tilde{\mathbb {S}}_a[P(z)] + \lambda _1 \frac{mz}{2}\tilde{\mathbb {S}}_a[P'(z)] + \lambda _2\left( \frac{mz}{2}\right) ^2\frac{\tilde{\mathbb {S}}_a[P''(z)]}{2!}, \end{aligned}\) B [ S ~ a [ P ( z ) ] ] = λ 0 S ~ a [ P ( z ) ] + λ 1 mz 2 S ~ a [ P ( z ) ] + λ 2 mz 2 2 S ~ a [ P ( z ) ] 2 ! , where \(0\le m \le n-1, \lambda _0, \lambda _1\) 0 m n - 1 , λ 0 , λ 1 , and \( \lambda _2\) λ 2 are such that all the zeros of \(\begin{aligned} u(z) = \lambda _0 + \left( {\begin{array}{c}m\\ 1\end{array}}\right) \lambda _1 z + \left( {\begin{array}{c}m\\ 2\end{array}}\right) \lambda _2 z^2, \end{aligned}\) u ( z ) = λ 0 + m 1 λ 1 z + m 2 λ 2 z 2 , lie in the half-plane \(Re \ z \le \frac{m}{4}\) R e z m 4 and obtain some compact generalizations of some well-known polynomial inequalities.