Riesz-Schur transforms.

par Javier Parcet (ICMAT Madrid)

mardi 18 nov. 2025, 14:00 → 15:00 Europe/Paris

Fokko (ICJ)

Riesz transforms are central operators in harmonic analysis, with applications in many other fields. I will start with a brief historical overview of dimension-free estimates for Riesz transforms in different settings. Next, we will also overview a powerful connection between Fourier multipliers (among which Riesz transforms are cornerstone examples) and certain class of Schur multipliers—linear maps on matrix algebras acting on them by entrywise multiplication. Finally, I will present new inequalities for Schur multipliers which extend dimension-free estimates for Riesz transforms. If time permits I will explore a few applications. Joint work with A. González-Pérez, J. Pérez-García and É. Ricard.