Sampling and Interpolation on Some Non-commutative Nilpotent Lie Groups

Abstract

Let $N$ be a non-commutative, simply connected, connected, two-step nilpotent Lie group with Lie algebra $\mathfrak{n}$ such that $\mathfrak{n=a\oplus b\oplus z}$, $\left[ \mathfrak{a},\mathfrak{b}\right] \subseteq \mathfrak{z},$ the algebras $\mathfrak{a},\mathfrak{b,z}$ are abelian, $\mathfrak{a}=\mathbb{R}\text{-span}\left\{ X_{1},X_{2},\cdots,X_{d}\right\} ,$ and $\mathfrak{b}=\mathbb{R}\text{-span}\left\{ Y_{1},Y_{2},\cdots ,Y_{d}\right\} .$ Also, we assume that $\det\left[ \left[ X_{i}% ,Y_{j}\right] \right] _{1\leq i,j\leq d}$ is a non-vanishing homogeneous polynomial in the unknowns $Z_{1},\cdots,Z_{n-2d}$ where $\left\{ Z_{1},\cdots,Z_{n-2d}\right\} $ is a basis for the center of the Lie algebra. Using well-known facts from time-frequency analysis, we provide some precise sufficient conditions for the existence of sampling spaces with the interpolation property, with respect to some discrete subset of $N$. The result obtained in this work can be seen as a direct application of time-frequency analysis to the theory of nilpotent Lie groups. Several explicit examples are computed. This work is a generalization of recent results obtained for the Heisenberg group by Currey, and Mayeli in \cite{Currey}.