Orthonormal Bases in the Orbit of Square-Integrable Representations of Nilpotent Lie Groups

Karlheinz Gröchenig, David Rottensteiner

Let $G$ be a connected, simply connected nilpotent group and $\pi$ be a square-integrable irreducible unitary representation modulo its center $Z(G)$ on $L^2({\mathbf{R}}^d)$. We prove…