(2025) To appear in Trends in Mathematics. With:
Duván CardonaIn this paper we investigate \(L^p\)-estimates for Hörmander classes of pseudo-differential operators on the torus \(\mathbb{T}^n\). Our results are framed within the global symbolic calculus developed by Ruzhansky and Turunen on \(\mathbb{T}^n \times \mathbb{Z}^n\), by using the discrete Fourier analysis on the torus. This approach extends the classical \((\rho, \delta)\)-Hörmander classes to the toroidal setting. The main contributions of this work generalize the method of Álvarez and Hounie for \(\mathbb{R}^n\) to the torus, while also extending Fefferman’s \(L^p\)-boundedness theorem to the toroidal context, even in cases where \(\delta \geq \rho\). When \(\delta \leq \rho\), our results align with and recover existing estimates found in the literature.