Problems on Discrete Metric Spaces

These problems were presented at the Third International Conference on Discrete Metric Spaces, held at CIRM, Luminy, France, 15{18 September 1998. The names of the originators of a problem are given where these are known and diierent from the presenter of the problem at the conference. Terminology: In a metric space, the point y is between x and z if d(x; y) + d(y; z) = d(x; z). A d-segment is a set of the form hx; zi of points between x and z. A set S is d-convex if, whenever x; z 2 S, then hx; zi S. The path metric in a connected graph G is deened by the rule that d(x; y) is the length of the shortest path from x to y.