Nonuniform Sampling and Recovery of Bandlimited Functions in Higher Dimensions

We provide sufficient conditions on a family of functions $(\phi_\alpha)_{\alpha\in A}:\mathbb{R}^d\to\mathbb{R}$ for sampling of multivariate bandlimited functions at certain nonuniform sequences of points in $\mathbb{R}^d$. We consider interpolation of functions whose Fourier transform is supported in some small ball in $\mathbb{R}^d$ at scattered points $(x_j)_{j\in\mathbb{N}}$ such that the complex exponentials $\left(e^{-i\langle x_j,\cdot\rangle}\right)_{j\in\mathbb{N}}$ form a Riesz basis for the $L_2$ space of a convex body containing the ball. Recovery results as well as corresponding approximation orders in terms of the parameter $\alpha$ are obtained.Comment: 17 pages. Submitte

Lattice Approximations in Wasserstein Space

We consider structured approximation of measures in Wasserstein space $W_p(\mathbb{R}^d)$ for $p\in[1,\infty)$ by discrete and piecewise constant measures based on a scaled Voronoi partition of $\mathbb{R}^d$. We show that if a full rank lattice $\Lambda$ is scaled by a factor of $h\in(0,1]$, then approximation of a measure based on the Voronoi partition of $h\Lambda$ is $O(h)$ regardless of $d$ or $p$. We then use a covering argument to show that $N$-term approximations of compactly supported measures is $O(N^{-\frac1d})$ which matches known rates for optimal quantizers and empirical measure approximation in most instances. Finally, we extend these results to noncompactly supported measures with sufficient decay