Abstract
A flow on a directed network is said to be confluent if the flow uses at most one outgoing arc at each node. Confluent flows arise naturally from destination-based routing. We study the Maximum Confluent Flow Problem (MaxConf) with a single commodity but multiple sources and sinks. Unlike previous results, we consider heterogeneous arc capacities. The supplies and demands of the sources and sinks can also be bounded. We give a pseudo-polynomial time algorithm and an FPTAS for graphs with constant treewidth. Somewhat surprisingly, MaxConf is NP-hard even on trees, so these algorithms are, in a sense, best possible. We also show that it is NP-complete to approximate MaxConf better than 3/2 on general graphs.
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References
Ford, L.R., Fulkerson, D.R.: Maximal flow through a network. Canadian Journal of Mathematics 8, 399–404 (1956)
Ahuja, R.K., Magnanti, T.L., Orlin, J.B.: Network Flows: Theory, Algorithms, and Applications. Prentice-Hall, Englewood Cliffs (1993)
Kleinberg, J.M.: Single-source unsplittable flow. In: 37th Annual Symposium on Foundations of Computer Science, pp. 68–77 (1996)
Bley, A.: Routing and Capacity Optimization for IP Networks. PhD thesis, TU Berlin (2007)
Fügenschuh, A., Homfeld, H., Schuelldorf, H.: Routing cars in rail freight service. Dagstuhl Seminar Proceedings, vol. 09261, Dagstuhl, Germany (2009)
Goyal, N., Olver, N., Shepherd, F.B.: The VPN conjecture is true. In: STOC 2008: Proceedings of the 40th annual ACM symposium on Theory of computing, pp. 443–450. ACM, New York (2008)
Chen, J., Rajaraman, R., Sundaram, R.: Meet and merge: approximation algorithms for confluent flows. J. Comput. Syst. Sci. 72, 468–489 (2006)
Chen, J., Kleinberg, R.D., Lovász, L., Rajaraman, R., Sundaram, R., Vetta, A.: (Almost) tight bounds and existence theorems for single-commodity confluent flows. J. ACM 54, 16 (2007)
Bodlaender, H.: Treewidth: Algorithmic techniques and results. In: Privara, I., Ružička, P. (eds.) MFCS 1997. LNCS, vol. 1295, pp. 29–36. Springer, Heidelberg (1997)
Fortune, S., Hopcroft, J., Wyllie, J.: The directed subgraph homeomorphism problem. Theoretical Computer Science 10, 111–121 (1980)
Garey, M.R., Johnson, D.S.: Computers and Intractability, A Guide to the Theory of NP-Completeness. W.H. Freeman and Company, New York (1979)
Johnson, T., Robertson, N., Seymour, P.D., Thomas, R.: Directed tree-width. Journal of Combinatorial Theory, Series B 82, 138–154 (2001)
Kaibel, V., Peinhardt, M.A.F.: On the bottleneck shortest path problem. Technical Report 06-22, Konrad-Zuse-Zentrum f. Informationstechnik Berlin (2006)
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Dressler, D., Strehler, M. (2010). Capacitated Confluent Flows: Complexity and Algorithms. In: Calamoneri, T., Diaz, J. (eds) Algorithms and Complexity. CIAC 2010. Lecture Notes in Computer Science, vol 6078. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-13073-1_31
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DOI: https://doi.org/10.1007/978-3-642-13073-1_31
Publisher Name: Springer, Berlin, Heidelberg
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