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arXiv · 1904.07930

Extensions of the vector-valued Hausdorff-Young inequalities

Oscar Dominguez·Mark Veraar
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Abstract

In this paper we study the vector-valued analogues of several inequalities for the Fourier transform. In particular, we consider the inequalities of Hausdorff--Young, Hardy--Littlewood, Paley, Pitt, Bochkarev and Zygmund. The Pitt inequalities include the Hausdorff--Young and Hardy--Littlewood inequalities and state that the Fourier transform is bounded from $L^p(\mathbb{R}^d,|\cdot|^{\beta p})$ into $L^q(\mathbb{R}^d,|\cdot|^{-\gamma q})$ under certain condition on $p,q,\beta$ and $\gamma$. Vector-valued analogues are derived under geometric conditions on the underlying Banach space such as Fourier type and related geometric properties. Similar results are derived for $\mathbb{T}^d$ and $\mathbb{Z}^d$ by a transference argument. We prove sharpness of our results by providing elementary examples on $\ell^p$-spaces. Moreover, connections with Rademacher (co)type are discussed as well.

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Oscar Dominguez, Mark Veraar. 2019-04-16. Extensions of the vector-valued Hausdorff-Young inequalities. https://arxiv.org/abs/1904.07930

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