On the ratio of the maximum term and the maximum modulus of the sum of two entire functions (Q1174914)

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scientific article; zbMATH DE number 9692
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On the ratio of the maximum term and the maximum modulus of the sum of two entire functions
scientific article; zbMATH DE number 9692

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    On the ratio of the maximum term and the maximum modulus of the sum of two entire functions (English)
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    25 June 1992
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    Let \(f(z)\) be an entire function, \(M(r,f)\) and \(\mu(r,f)\) be the maximum modulus of \(f(z)\) and the maximum term of \(f(z)\). Let \(M_ k\) be the class of all entire functions \(f\) for which \[ \limsup_{r\to\infty} {{\mu(r,f)} \over {M(r,f)}}=k. \] Though the set of all entire functions is closed under addition, the author here proves that the sum of any two transcendental entire functions belonging to \(M_ k\) need not belong to the same class \(M_ k\). For any \(f_ 1\in M_ k\) (\(0\leq k<1\)) he constructs an \(f_ 2(z)\in M_ k\) such that \(f_ 1(z)+f_ 2(z)\) is a transcendental entire function in \(M_ 1\). Given a transcendental entire function \(f_ 1\in M_ 1\) he finds another entire function \(f_ 2\in M\), such that \(f_ 1+f_ 2\in M_ k\), \(k\neq 1\).
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    maximum modulus
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    maximum term
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