Waypoint routing on bounded treewidth graphs

On Routing Disjoint Paths in Bounded Treewidth Graphs

We study the problem of routing on disjoint paths in bounded treewidth graphs with both edge and node capacities. The input consists of a capacitated graph G and a collection of k source-destination pairsM = {(s1, t1), . . . , (sk, tk)}. The goal is to maximize the number of pairs that can be routed subject to the capacities in the graph. A routing of a subsetM′ of the pairs is a collection P o...

Recoloring bounded treewidth graphs

Let k be an integer. Two vertex k-colorings of a graph are adjacent if they differ on exactly one vertex. A graph is k-mixing if any proper k-coloring can be transformed into any other through a sequence of adjacent proper k-colorings. Any graph is (tw + 2)-mixing, where tw is the treewidth of the graph (Cereceda 2006). We prove that the shortest sequence between any two (tw + 2)-colorings is a...

On bounded treewidth duality of graphs

Channel assignment on graphs of bounded treewidth

The following ‘constraint matrix span problem’ arises in the assignment of radio channels in cellular communications systems. Given a graph G with a positive integer length l(xy) for each edge xy, and given a positive integer B, can we assign to each vertex x a channel (x) from 1; : : : ; B such that | (x)− (y)|¿ l(xy) for each edge xy? We show that this problem is NP-complete for graphs of tre...

Replica Placement on Bounded Treewidth Graphs

We consider the replica placement problem: given a graph with clients and nodes, place replicas on a minimum set of nodes to serve all the clients; each client is associated with a request and maximum distance that it can travel to get served and there is a maximum limit (capacity) on the amount of request a replica can serve. The problem falls under the general framework of capacitated set cov...