Precise fundamental inequalities and sum of deficiencies (Q1177974)

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scientific article; zbMATH DE number 22589
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Precise fundamental inequalities and sum of deficiencies
scientific article; zbMATH DE number 22589

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    Precise fundamental inequalities and sum of deficiencies (English)
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    26 June 1992
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    In 1959 W. K. Hayman proved the following theorem: Let \(f\) be a transcendental meromorphic function in the plane and \(k\) be a positive integer. Then \[ T(r,f)<(2+1/k)N\left(r,{1\over f}\right)+(2+2/k)\overline N\left(r,{1\over f^{(k)}-1}\right)+S(r,f). \] The author improves this result remarkably. Under the same assumptions he shows that for \(\varepsilon>0\) \[ T(r,f)<(1+1/k)N\left(r,{1\over f}\right)+(1+1/k)N\left(r,{1\over f^{(k)}-1}\right)-N\left(r,{1\over f^{(k+1)}}\right)+\varepsilon T(r,f)+S(r,f). \] He also proves several inequalities for meromorphic functions and their derivatives and gives some estimates to the sum of deficiencies.
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    Hayman's alternative
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    inequalities
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    meromorphic functions
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    derivatives
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    deficiencies
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    value distribution
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