Endpoint Estimates for Commutators of the Dirichlet Riesz Transform on the Half-Space

Let $\mathfrak R=\nabla(-Δ_D)^{-1/2}$ be the Riesz transform associated with the Dirichlet Laplacian on the upper half-space $\mathbb R^n_+$, and let $H^1_r(\mathbb R^n_+)$ denote the Hardy space of restrictions. We establish an endpoint theory for commutators with $\mathfrak R$ on $H^1_r(\mathbb R^