Some Integral Mean Estimates for Polynomials with Restricted Zeros  

作　　者：Abdullah Mir Q.M.Dawood Bilal Dar 

机构地区：[1]Department of Mathematics, University of Kashmir

出　　处：《Analysis in Theory and Applications》2015年第1期81-91,共11页分析理论与应用（英文刊）

基　　金：supported by UGC under major research project scheme vide No. MRP-MAJOR-MATH-2013-29143

摘　　要：Let P（z） be a polynomial of degree n having all its zeros in ｜z｜≤ k. For k = 1, it is known that for each r 〉 0 and ｜a｜≥1,n（｜a｜-1）{∫0^2π｜P（e^iθ）｜^rdθ}^1/r≤{∫0^2π｜1＋e^iθ｜^rdθ}^1/rmax｜z｜=1｜DzP（z）｜.In this paper, we shall first consider the case when k≥1 and present certain generaliza- tions of this inequality. Also for k≤ 1, we shall prove an interesting result for Lacunary type of polynomials from which many results can be easily deduced.Let P（z） be a polynomial of degree n having all its zeros in ｜z｜≤ k. For k = 1, it is known that for each r 〉 0 and ｜a｜≥1,n（｜a｜-1）{∫0^2π｜P（e^iθ）｜^rdθ}^1/r≤{∫0^2π｜1＋e^iθ｜^rdθ}^1/rmax｜z｜=1｜DzP（z）｜.In this paper, we shall first consider the case when k≥1 and present certain generaliza- tions of this inequality. Also for k≤ 1, we shall prove an interesting result for Lacunary type of polynomials from which many results can be easily deduced.

关 键 词：POLYNOMIAL ZEROS polar derivative. 

分 类 号：O172.2[理学—数学]