INSTANCE:
Graph
,
weight
and length
for each ,
positive integer B.
SOLUTION:
A spanning subgraph
for G such that the sum of the weights
of the edges in E' does not exceed B.
MEASURE:
The diameter of the spanning subgraph.
Bad News:
Not approximable within 2
for any
[405].
Comment:
Not approximable within 3/2
for planar graphs.
Not approximable within 5/4
if l(e)=1 for every edge e
[405].
For results on minimum Steiner trees of bounded diameter, see MINIMUM STEINER TREE.