- INSTANCE: Graph , a set of terminals ,a buy cost function , a distance cost , cost bound and length bound .
- SOLUTION: A tree in G such that , , , , such that the diameter under -cost is at most and buy cost is at most .
- COST FUNCTION:
- OBJECTIVE: Minimize.
*Approx.:*Admits an -approximation algorithm [58].*Hardness:*NP-hard to approximate within for some constant [58].

2015-04-27 Revision: 288 PDF version