We find optimal conditions on m-linear Fourier multipliers that give rise to bounded operators from products of Hardy spaces , , to Lebesgue spaces . These conditions are expressed in terms of L²-based Sobolev spaces with sharp indices within the classes of multipliers we consider. Our results extend those obtained in the linear case (m = 1) by Calderón and Torchinsky (1977) and in the bilinear case (m = 2) by Miyachi and Tomita (2013). We also prove a coordinate-type Hörmander integral condition which we use to obtain certain endpoint cases.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-cm6771-10-2015, author = {Loukas Grafakos and Hanh Van Nguyen}, title = {Multilinear Fourier multipliers with minimal Sobolev regularity, I}, journal = {Colloquium Mathematicae}, volume = {144}, year = {2016}, pages = {1-30}, zbl = {1339.42012}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-cm6771-10-2015} }
Loukas Grafakos; Hanh Van Nguyen. Multilinear Fourier multipliers with minimal Sobolev regularity, I. Colloquium Mathematicae, Tome 144 (2016) pp. 1-30. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-cm6771-10-2015/