A light metric spanner

It has long been known that d-dimensional Euclidean point sets admit (1 broken vertical bar epsilon)-stretch spanners with lightness W-E = epsilon(-O(d)), that is the total edge weight is at most W-E times the weight of the minimum spanning tree of the set [DHN93]. Whether or not a similar result holds for metric spaces with low doubling dimension has remained an open problem. In this paper, we resolve the question in the affirmative, and show that doubling spaces admit (1 + epsilon)-stretch spanners with lightness W-D = (ddim/epsilon)(O(ddim)).