A version of Littlewood–Paley–Rubio de Francia inequality for the two-parameter Walsh system is proved: for any family of disjoint rectangles \( {I}_k={I}_k^1\times {I}_k^2 \) in ℤ+ × ℤ+ and a family of functions fk with Walsh spectrum inside Ik the following is true:
where Cp does not depend on the choice of rectangles {Ik} or functions {fk}. The arguments are based on the atomic theory of two-parameter martingale Hardy spaces. In the course of the proof, a two-parameter version of Gundy’s theorem on the boundedness of operators taking martingales to measurable functions is formulated, which might be of independent interest.
Similar content being viewed by others
References
V. Borovitskiy, “Weighted Littlewood–Paley Inequality for Arbitrary Rectangles in ℝ2,” St. Petersburg Math. J., 32, No. 6, 975–997 (2021).
J. Bourgain, “On square functions on the trigonometric system,” Bull. Soc. Math. Belg. S´er. B, 37, No. 1, 20–26 (1985).
J. Brossard, “Comparaison des “Normes” Lp du Processus Croissant et de la Variable Maximale Pour Les Martingales Régulières à Deux Indices. Théorème Local Correspondant,” Ann. Probab., 8, No. 6, 1183–1188 (1980).
J. Brossard, “Régularitédes martingales à deux indices et inégalités de normes,” Processus Aléatoires à Deux Indices, Springer, 1981, pp. 91–121.
R. Fefferman, “Calderon–Zygmund theory for product domains: Hp spaces,” Proceedings of the National Academy of Sciences, 83, No. 4, 840–843 (1986).
R. F. Gundy, “Inégalités pour martingales à un et deux indices: L’espace Hp,” Ecole d’étéde probabilités de Saint-Flour viii-1978, Springer, pp. 251–334, 1980.
R. F. Gundy, “A decomposition for L1-bounded martingales,” Ann. Math. Statist., 39, No. 1, 134–138 (1968).
J.-L. Journé, “Calderón–Zygmund operators on product spaces,” Revista matem´atica iberoamericana, 1, No. 3, 55–91 (1985).
S. V. Kislyakov, “Littlewood–Paley theorem for arbitrary intervals: Weighted estimates,” J. Math. Sci., 156, No. 5, 824–833 (2009).
S. V. Kislyakov, “Martingale transforms and uniformly convergent orthogonal series,” J. Sov. Math., 37, No. 5, 1276–1287 (1987).
S. V. Kislyakov and D. V. Parilov, “On the Littlewood–Paley theorem for arbitrary intervals,” J. Math. Sci., 139, No. 2, 6417–6424 (2006).
M. T. Lacey, “Issues related to Rubio de Francia’s Littlewood–Paley Inequality: A Survey,” ar**v preprint math/0306417 (2003).
J. E. Littlewood and R. E. A. C. Paley, “Theorems on Fourier series and power series,” J. London Math. Soc., 1, No. 3, 230–233 (1931).
E. Malinnikova and N. N. Osipov, “Two types of Rubio de Francia operators on Triebel–Lizorkin and Besov spaces,” J. Fourier Anal. Appl., 25, No. 3, 804–818 (2019).
Ch. Métraux, “Quelques inégalités pour martingales à paramétre bidimensionnel,” Séminaire de Probabilités XII, Springer, 1978, pp. 170–179.
N. Osipov, “Littlewood–Paley–Rubio de Francia inequality for the Walsh system,” St. Petersburg Math. J., 28, No. 5, 719–726 (2017).
N. Osipov, “Littlewood–Paley inequality for arbitrary rectangles in ℝ2 for 0 < p ≤ 2,” St. Petersburg Math. J., 22, No. 2, 293–306 (2011).
N. N. Osipov, “The Littlewood–Paley–Rubio de Francia inequality in Morrey-Campanato spaces,” Sbornik: Mathematics, 205, No. 7, 1004 (2014).
N. N. Osipov, “One-sided Littlewood–Paley inequality in ℝn for 0 < p ≤ 2,” J. Math. Sci., 172, No. 2, 229–242 (2011).
R. E. A. C. Paley, “A remarkable series of orthogonal functions,” Proc. London Math. Soc., 34, No. 1, 241–279 (1931).
R. de Francia and L. José, “A Littlewood–Paley inequality for arbitrary intervals,” Revista Matematica Iberoamericana, 1, No. 2, 1–14 (1985).
F. Soria, “A note on a Littlewood–Paley inequality for arbitrary intervals in ℝ2,” J. London Math. Soc., 2, No. 1, 137–142 (1987).
F. Weisz, “Cesaro summability of two-parameter Walsh–Fourier series,” J. Approx. Theory, 88, No. 2, 168–192 (1997).
F. Weisz, Martingale Hardy Spaces and their Applications in Fourier Analysis, Springer, 2006.
Author information
Authors and Affiliations
Corresponding author
Additional information
Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 491, 2020, pp. 27–42.
Rights and permissions
About this article
Cite this article
Borovitskiy, V. Littlewood–Paley–Rubio De Francia Inequality for the Two-Parameter Walsh System. J Math Sci 261, 746–756 (2022). https://doi.org/10.1007/s10958-022-05785-0
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10958-022-05785-0