Some Sharpening and Generalizations of a Result of T. J. Rivlin

Let p(z) = a0+a1z+a2z^2+a3z3+…+anz^n be a polynomial of degree n. Rivlin [12] proved that if p (z) ≠ 0 in the unit disk, then for 0 〈 r ≤ 1,max(|r+1|/2)^n max|p(z)|.|z|=1In this paper, we prove a sharpening and generalization of this result and show by means of examples that for some polynomials our...

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Bibliographic Details
Published in分析理论与应用:英文刊 Vol. 33; no. 3; pp. 219 - 228
Main Author N. K. Govil;Eze R. Nwaeze
Format Journal Article
LanguageChinese
Published 2017
Online AccessGet full text
ISSN1672-4070
1573-8175

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Summary:Let p(z) = a0+a1z+a2z^2+a3z3+…+anz^n be a polynomial of degree n. Rivlin [12] proved that if p (z) ≠ 0 in the unit disk, then for 0 〈 r ≤ 1,max(|r+1|/2)^n max|p(z)|.|z|=1In this paper, we prove a sharpening and generalization of this result and show by means of examples that for some polynomials our result can significantly improve the bound obtained by the Rivlin's Theorem.
Bibliography:32-1631/O1
Let p(z) = a0+a1z+a2z^2+a3z3+…+anz^n be a polynomial of degree n. Rivlin [12] proved that if p (z) ≠ 0 in the unit disk, then for 0 〈 r ≤ 1,max(|r+1|/2)^n max|p(z)|.|z|=1In this paper, we prove a sharpening and generalization of this result and show by means of examples that for some polynomials our result can significantly improve the bound obtained by the Rivlin's Theorem.
Inequalities, polynomials, zeros.
ISSN:1672-4070
1573-8175