Abstract
It is proved that a trigonometric cosine series of the form Σ Emphasis>=0/∞ n a n cos(nx) with nonnegative coefficients can be constructed in such a way that all of its partial sums are positive on the real axis. It converges to zero almost everywhere and is not a Fourier-Lebesgue series. Some other properties of trigonometric series with nonnegative partial sums are also studied.
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Translated fromMatematicheskie Zametki, Vol. 59, No. 1, pp. 24–41, January, 1996.
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Belov, A.S. Non-Fourier-Lebesgue trigonometric series with nonnegative partial sums. Math Notes 59, 18–30 (1996). https://doi.org/10.1007/BF02312461
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DOI: https://doi.org/10.1007/BF02312461