Spectral multipliers and wave equation for sub-Laplacians: lower regularity bounds of Euclidean type

Alessio Martini, Detlef Müller, Sebastiano Nicolussi Golo

Let $\mathcal{L}$ be a smooth second-order real differential operator in divergence form on a manifold of dimension $n$. Under a bracket-generating condition, we show that the rang…