Trigonometric polynomials with frequencies in the set of cubes

Autor: Gabdullin, Mikhail R., Konyagin, Sergei V.
Rok vydání: 2023
Předmět:
Druh dokumentu: Working Paper
Popis: We prove that for any $\epsilon>0$ and any trigonometric polynomial $f$ with frequencies in the set $\{n^3: N \leq n\leq N+N^{2/3-\epsilon}\}$, one has $$ \|f\|_4 \ll \epsilon^{-1/4}\|f\|_2 $$ with implied constant being absolute. We also show that the set $\{n^3: N\leq n\leq N+(0.5N)^{1/2}\}$ is a Sidon set.
Comment: 6 pages; inaccuracy in the proof of the main theorem is corrected
Databáze: arXiv