Glasnik Matematicki, Vol. 38, No.2 (2003), 269-272.

A GENERALIZATION OF A RESULT ON MAXIMUM MODULUS OF POLYNOMIALS

V. K. Jain

Mathematics Department, Indian Institute of Technology, Kharagpur - 721302, India
e-mail: vkj@maths.iitkgp.ernet.in


Abstract.   For an arbitrary entire function f(z), let M(f,d) = max|z|=d |f(z)|. It is known that if the geometric mean of the moduli of the zeros of a polynomial p(z) of degree n is at least 1, and M(p,1) = 1, then for R > 1, M(p,R) ≤ R/2 + 1/2 if n = 1,

M(p,R) ≤ Rn/2 + (3+2√2)Rn-2/2 if n ≥ 2.

We have obtained a generalization of this result, by assuming the geometric mean of the moduli of the zeros of the polynomial to be at least k, (k > 0).

2000 Mathematics Subject Classification.   30C10, 30A10.

Key words and phrases.   Polynomials, zeros, geometric mean, maximum modulus.


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