Non-real zeros of derivatives of meromorphic functions
نویسندگان
چکیده
منابع مشابه
Non-real Zeros of Derivatives of Real Meromorphic Functions
The main result of the paper determines all real meromorphic functions f of finite order in the plane such that f ′ has finitely many zeros while f and f(k), for some k ≥ 2, have finitely many non-real zeros. MSC 2000: 30D20, 30D35.
متن کاملZeros of differential polynomials in real meromorphic functions
We investigate when differential polynomials in real transcendental meromorphic functions have non-real zeros. For example, we show that if g is a real transcendental meromorphic function, c ∈ R \ {0} and n ≥ 3 is an integer, then g′gn − c has infinitely many non-real zeros. If g has only finitely many poles, then this holds for n ≥ 2. Related results for rational functions g are also considered.
متن کاملZeros of differences of meromorphic functions
Let f be a function transcendental and meromorphic in the plane, and define g(z) by g(z) = ∆f(z) = f(z+1)− f(z). A number of results are proved concerning the existence of zeros of g(z) or g(z)/f(z), in terms of the growth and the poles of f . The results may be viewed as discrete analogues of existing theorems on the zeros of f ′ and f ′/f . MSC 2000: 30D35.
متن کاملSlowly growing meromorphic functions and the zeros of differences
Let f be a function transcendental and meromorphic in the plane with lim inf r→∞ T (r, f) (log r)2 = 0. Let q ∈ C with |q| > 1. It is shown that at least one of the functions F (z) = f(qz)− f(z), G(z) = F (z) f(z) has infinitely many zeros. This result is sharp. MSC 2000: 30D35.
متن کاملProof of a conjecture of Pólya on the zeros of successive derivatives of real entire functions
We prove Pólya’s conjecture of 1943: For a real entire function of order greater than 2 with finitely many non-real zeros, the number of non-real zeros of the n-th derivative tends to infinity as n → ∞ . We use the saddle point method and potential theory, combined with the theory of analytic functions with positive imaginary part in the upper half-plane.
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ژورنال
عنوان ژورنال: Journal d'Analyse Mathématique
سال: 2017
ISSN: 0021-7670,1565-8538
DOI: 10.1007/s11854-017-0031-6