We show that it is possible for an L2 function on the circle, which is a sum of an almost everywhere convergent series of exponentials with positive frequencies, to not belong to the Hardy space H2. A consequence in the uniqueness theory is obtained.
Il existe une série trigonométrique dont toutes les fréquences sont positives et qui converge presque partout vers une fonction de carré intégrable qui admet des fréquences négatives. Ce fait est équivalent à l'existence de la série trigonométrique mentionnée dans le titre. Il s'agit donc d'une contribution à la théorie de l'unicité du développement trigonométrique.
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@article{CRMATH_2003__336_6_475_0, author = {Kozma, Gady and Olevskiǐ, Alexander}, title = {A null series with small anti-analytic part}, journal = {Comptes Rendus. Math\'ematique}, pages = {475--478}, publisher = {Elsevier}, volume = {336}, number = {6}, year = {2003}, doi = {10.1016/S1631-073X(03)00097-9}, language = {en}, url = {https://www.numdam.org/articles/10.1016/S1631-073X(03)00097-9/} }
TY - JOUR AU - Kozma, Gady AU - Olevskiǐ, Alexander TI - A null series with small anti-analytic part JO - Comptes Rendus. Mathématique PY - 2003 SP - 475 EP - 478 VL - 336 IS - 6 PB - Elsevier UR - https://www.numdam.org/articles/10.1016/S1631-073X(03)00097-9/ DO - 10.1016/S1631-073X(03)00097-9 LA - en ID - CRMATH_2003__336_6_475_0 ER -
%0 Journal Article %A Kozma, Gady %A Olevskiǐ, Alexander %T A null series with small anti-analytic part %J Comptes Rendus. Mathématique %D 2003 %P 475-478 %V 336 %N 6 %I Elsevier %U https://www.numdam.org/articles/10.1016/S1631-073X(03)00097-9/ %R 10.1016/S1631-073X(03)00097-9 %G en %F CRMATH_2003__336_6_475_0
Kozma, Gady; Olevskiǐ, Alexander. A null series with small anti-analytic part. Comptes Rendus. Mathématique, Volume 336 (2003) no. 6, pp. 475-478. doi : 10.1016/S1631-073X(03)00097-9. https://www.numdam.org/articles/10.1016/S1631-073X(03)00097-9/
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