Fourier analysis on a class of Schwartz spaces and applications

Abstract

The study of regularity and solvability of partial differential operators on non-compact manifolds requires the construction of adapted functional spaces. In this work we introduce $\mathcal{S}(\mathfrak{M}\times\mathbb{R}^n)$, the Schwartz space on the product of a homogeneous space $\mathfrak{M}$ and the Euclidean space $\mathbb{R}^n$. We characterize $\mathcal{S}(\mathfrak{M}\times\mathbb{R}^n)$ and its topological dual by employing discrete Fourier analysis in terms of eigenfunction expansions associated with a class of anisotropic elliptic operators on $\mathbb{R}^n$. We provide a characterization via partial Fourier coefficients and via full coefficients, that is, with respect to both components of $\mathfrak{M} \times \mathbb{R}^n$ simultaneously, which is achieved by studying the Fourier analysis on $\mathfrak{M}$. Our results provide new tools for the analysis of operators in this broader setting. As an application, we investigate the global existence and regularity of solutions for a class of partial differential equations on $\mathfrak{M}\times \mathbb{R}^n$.