摘要

We give a simple sufficient condition for a weighted graph to have a diameter-preserving spanning tree. More precisely, let G = (V, E, f(E)) be a connected edge weighted graph with f(E) being the edge weight function. Let f(V) be the vertex weight function of G induced by f(E) as follows: f(V)(v) = max{f(E)(e) : e is incident with v} for all v is an element of V. We show that G contains a diameter-preserving spanning tree if d(G) >= 2/3 Sigma(v is an element of V) f(V)(v) where d(G) is the diameter of G. The condition is sharp in the sense that for any is an element of > 0, there exist weighted graphs G satisfying d(G) > (2/3-is an element of) Sigma(v is an element of V) f(V)(v) and not containing a diameter-preserving spanning tree.