Unsplittable Flow in Paths and Trees and Column-Restricted Packing Integer Programs
APPROX '09 / RANDOM '09 Proceedings of the 12th International Workshop and 13th International Workshop on Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques
Iterative packing for demand and hypergraph matching
IPCO'11 Proceedings of the 15th international conference on Integer programming and combinatoral optimization
On k-column sparse packing programs
IPCO'10 Proceedings of the 14th international conference on Integer Programming and Combinatorial Optimization
Topology-aware VM migration in bandwidth oversubscribed datacenter networks
ICALP'12 Proceedings of the 39th international colloquium conference on Automata, Languages, and Programming - Volume Part II
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We examine formulations for the well-known b-matching problem in the presence of integer demands on the edges. A subset M of edges is feasible if for each node v the total demand of edges in M incident to v is at most bv. We examine the system of star inequalities for this problem. This system yields an exact linear description for b-matchings in bipartite graphs. For the demand version, we show that the integrality gap for this system is at least 2.5 and at most 2.764. For general graphs, the gap lies between 3 and 3.264. We also describe a 3-approximation algorithm (2.5 for bipartite graphs) for the cardinality version of the problem. A fully polynomial approximation scheme is also presented for the problem on a tree, thus generalising a well-known result for the knapsack problem. Recently, the notion of demand matching has arisen in the design of Clos network switches.