Fejér means of two-dimensional Fourier transforms on $H_p(ℝ × ℝ)$

Ferenc Weisz¹

¹

Colloquium Mathematicum, Tome 82 (1999) no. 2, pp. 155-166.

Résumé

The two-dimensional classical Hardy spaces $H_p(ℝ × ℝ)$ are introduced and it is shown that the maximal operator of the Fejér means of a tempered distribution is bounded from $H_p(ℝ × ℝ)$ to $L_p(ℝ^2)$ (1/2 p ≤ ∞) and is of weak type $(H^{#}_1 (ℝ × ℝ), L_1(ℝ^2))$ where the Hardy space $H^#_1(ℝ × ℝ)$ is defined by the hybrid maximal function. As a consequence we deduce that the Fejér means of a function f ∈ $H_1^#(ℝ × ℝ)$ ⊃ $LlogL(ℝ^2)$ converge to f a.e. Moreover, we prove that the Fejér means are uniformly bounded on $H_p(ℝ × ℝ)$ whenever 1/2 p ∞. Thus, in case f ∈ $H_p(ℝ × ℝ)$, the Fejér means converge to f in $H_p(ℝ × ℝ)$ norm (1/2 p ∞). The same results are proved for the conjugate Fejér means.

Détail

DOI : 10.4064/cm-82-2-155-166

Keywords: p-atom, Hardy spaces, atomic decomposition, interpolation, Fejér means