Generating Low-Degree 2-Spanners

Generating Sparse 2-spanners

A k?spanner of a connected graph G = (V; E) is a subgraph G 0 consisting of all the vertices of V and a subset of the edges, with the additional property that the distance between any two vertices in G 0 is larger than that distance in G by no more than a factor of k. This note concerns the problem of nding the sparsest 2-spanner in a given graph, and presents an approximation algorithm for thi...

Lattice Spanners of Low Degree

Let δ0(P, k) denote the degree k dilation of a point set P in the domain of plane geometric spanners. If Λ is the infinite square lattice, it is shown that 1+ √ 2 ≤ δ0(Λ, 3) ≤ (3+2 √ 2) 5−1/2 = 2.6065 . . . and δ0(Λ, 4) = √ 2. If Λ is the infinite hexagonal lattice, it is shown that δ0(Λ, 3) = 1 + √ 3 and δ0(Λ, 4) = 2. All our constructions are planar lattice tilings constrained to degree 3 or 4.

Bounded Degree Planar Geometric Spanners

Given a set P of n points in the plane, we show how to compute in O(n logn) time a subgraph of their Delaunay triangulation that has maximum degree 7 and is a strong planar t-spanner of P with t = (1 + √ 2) ∗ δ, where δ is the spanning ratio of the Delaunay triangulation. Furthermore, given a Delaunay triangulation, we show a distributed algorithm that computes the same bounded degree planar sp...

Spanners of bounded degree graphs

On Plane Constrained Bounded-Degree Spanners

Let P be a finite set of points in the plane and S a set of non-crossing line segments with endpoints in P . The visibility graph of P with respect to S, denoted Vis(P, S), has vertex set P and an edge for each pair of vertices u, v in P for which no line segment of S properly intersects uv. We show that the constrained half-θ6-graph (which is identical to the constrained Delaunay graph whose e...