Let P and S be two disjoint sets of n and m points in the plane,
respectively. We consider the problem of computing a Steiner tree whose
Steiner vertices belong to S, in which each point of P is a leaf,
and whose longest edge length is minimum. We present an algorithm that
computes such a tree in O((n+m) log m) time, improving the previously
best result by a logarithmic factor. We also prove a matching lower
bound in the algebraic computation tree model.
Joint work with Ahmad and Anil.