Abstract
We prove that there is a sequence of trigonometric polynomials with positive integer coefficients, which converges to zero almost everywhere. We also prove that there is a function f: ℝ → ℝ such that the sums of its shifts are dense in all real spaces L p (ℝ) for 2 ≤ p < ∞ and also in the real space C0(R).
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Dedicated to the memory of Jean-Pierre Kahane
The research of both authors was supported by the grant of the Government of the Russian Federation (project 14.W03.31.0031).
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Borodin, P.A., Konyagin, S.V. Convergence to Zero of Exponential Sums with Positive Integer Coefficients and Approximation by Sums of Shifts of a Single Function on the Line. Anal Math 44, 163–183 (2018). https://doi.org/10.1007/s10476-018-0204-2
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DOI: https://doi.org/10.1007/s10476-018-0204-2
Key words and phrases
- trigonometric polynomial with positive integer coefficients
- convergence almost everywhere
- approximation
- sum of shifts
- L p space