Voronoi Diagrams in Higher Dimensions under Certain Polyhedral Distance Functions
Abstract
The paper bounds the combinatorial complexity of the Voronoi diagram of a set of points under certain polyhedral distance functions. Specifically, if $ß$ is a set of $n$ points in general position in $\Ee maximum complexity of its Voronoi diagram under the $\Linf$ metric, and also under a simplicial distance function, are both shown to be $\Theta(n^{\lceil d/2 \rceil})$. The upper bound for the case of the $\Linf$ metric follows from a new upper bound, also proved in this paper, on the maximum complexity of the union of $n$ axis-parallel hypercubes in $\E complexity isof $\Theta(n^{\ceil{d/2}})$, for $d \ge 1$, and it improves to $\Theta(n^{\floor{d/2}})$, for $d \ge 2$, if all the hypercubes have the same size. Under the $L_1$ metric, the maximum complexity of the Voronoi diagram of a set of $n$ points in general position in $\Eown to be d $\Theta(n^2)$. We also show that the general position assumption is essential, and give examples where the complexity of the diagram increases significantly when the points are in degenerate configurations. Finally, on-line algorithms are proposed for computing the Voronoi diagram of $n$ points in $\E under a simplicial or $\Linf$ distance function. Their randomized complexities are $O(n \log n + n ^{\ceil{d/2}})$ for simplicial diagrams and $O(n ^{\ceil{d/2}} \log ^{d-1} n)$ for $\Linf$-diagrams.