# Where i can find the proof of Ostrowski theorem

Where i can find any proof of next theorem?

Theorem of Ostrowski: Let $\sum_{n=0}^{\infty}a_nz^n$ be a power series with radius of convergence 1, which is analytically continuable beyond unit disk. Then the power series is overconvergent if it possesses Hadamard-Ostrowski gaps.

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## 1 Answer

In English, in the book by P. Dienes, The Taylor series, Dover, NY, 1957. In German: in the original A. Ostrowski's paper.

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Thank you Alexandre :) – Budget Mar 14 '13 at 19:31
@Alexandre, Can you give a reference for the Ostrowski paper? – Drew Armstrong May 23 '13 at 17:38