Abstract
In this paper, we consider integral (and fractional) packing problems in generalized kernel systems with a mixed family (gksmf). This framework generalizes combinatorial packing problems of several structures as, for instance, st-flows, arborescences, kernel systems, branchings, convex branchings, and covers in bi-set systems. We provide an algorithm, which improves by a factor of 2 on the upperbound for the size of a packing in a gksmf, provided by Leston-Rey and Wakabayashi. This in turn implies the following upperbounds, where n is the number of vertices, m the number of arcs, and r the number of root-sets of a digraph: m for the size of a packing of st-paths; \(m-n+2\) for the size of a packing of spanning arborescences; \(m+r-1\) for the size of a packing of spanning branchings; \(m+r-1\) for the size of a packing of Fujishige’s convex branchings; m for the size of a packing of dijoins of a restricted form; and \(m+r-1\) for the size of a packing in Frank’s bi-set systems with the mixed intersection property. Next, we consider the framework of uncrossing gksmf. We describe an algorithm for computing a packing in such a framework with the same upperbound guarantee. The time complexity of this algorithm implies an improvement over the best time complexity bounds known for computing a packing of spanning arborescences of Gabow and Manu, for computing a packing of spanning branchings of Lee and Leston-Rey, and for computing a packing of covers in a bi-set system with the mixed intersection property of Bérczi and Frank.
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References
Barahona, F.: Fractional packing of \(T\)-joins. SIAM J. Discrete Math. 17, 661–669 (2004)
Bérczi, K., Frank, A.: Variations for Lovász submodular ideas. In: Grötschel, M., Katona, G.O.H. (eds.) Building Bridges Between Mathematics and Computer Science, Bolyai Society, Series: Mathematical Studies, 19, pp. 137–164. Springer, Berlin (2008)
Bérczi, K., Frank, A.: Packing Arborescences. Technical report 2009-4, Egerváry Research Group
Cook, W., Fonlupt, J., Schrijver, A.: An integer analogue of Carathéodory’s theorem. J. Comb. Theory Ser. B 40, 63–70 (1986)
Edmonds, J.: Edge-disjoint branchings. In: Rustin B (ed) Combinatorial Algorithms, pp. 91–96. Academic Press, New York (1973)
Feofiloff, P., Younger, D.H.: Directed cut transversal packing for source-sink connected graphs. Combinatorica 7, 255–263 (1987)
Frank, A.: Kernel systems of directed graphs. Acta Sci. Math. (Szeged) 41(1–2), 63–76 (1979)
Frank, A.: Increasing the rooted-connectivity of a digraph by one. Math. Program. 84, 565–576 (1999)
Frank, A.: Connections in combinatorial optimization. Oxford Lectures in Mathematics and its Applications, vol. 38. Oxford University Press, Oxford (2011)
Frank, A.: Rooted \(k\)-connections in digraphs. Discrete Appl. Math. 157, 1242–1254 (2009)
Fujishige, S.: A note on disjoint arborescences. Combinatorica 30, 247–252 (2010)
Gabow, H.N., Manu, K.S.: Packing algorithms for arborescences (and spanning trees) in capacitated graphs. Math. Program. 82, 83–109 (1998)
Gijswijt, D., Regts, G.: On the Caratheodory Rank of Polymatroid Bases. arXiv:1003.1079 (2010)
Hao, J., Orlin, J.B.: A faster algorithm for finding the minimum cut in a directed graph. J. Algorithms 17(3), 424–446 (1994)
Kamiyama, N., Katoh, N., Takizawa, A.: Arc-disjoint in-trees in directed graphs. In: Proceedings of the 19th Annual ACM-SIAM Symposium on Discrete Algorithms, pp. 518–526 (2008)
Lee, O., Leston-Rey, M.: A faster algorithm for packing branchings in digraphs. Discrete Math. Appl. (2015). doi:10.1016/j.dam.2015.05.016
Leston-Rey, M.: Integral packing of branchings in capacitated digraphs. J. Comb. Optim. (2014). doi:10.1007/s10878-014-9768-3
Leston-Rey, M.: Um Arcabouço Generalizado Para Empacotamento de Ramificacões e Outras Estruturas Combinatórias, in Portuguese. Ph.D. Thesis (2012)
Leston-Rey, M., Wakabayashi, Y.: Packing in generalized kernel systems. Math. Program. Ser. A 149(1–2), 209–251 (2015)
Lovász, L.: On two minimax theorems on graph theory. J. Comb. Theory Ser. B 21, 96–103 (1976)
Matsuoka, Y.: Fractional packing in ideal clutters. Math. Program. 133(1–2), 159–169 (2012)
Pevzner, P.A.: Branching packing in weighted graphs. Selected Topics in Discrete Mathematics, American Mathematical Society Translations Series 2, vol. 158, pp. 185–200. American Mathematical Society, Providence, Rhode Island (1994)
de Pina, J.C., Soares, J.: A new bound for the Carathéodory rank of the bases of a matroid. J. Comb. Theory Ser. B 88, 323–327 (2003)
Schrijver, A.: Min-max relations for directed graphs. In: Bachem, A., Grotschel, M., Korte, B. (eds.) Bonn Workshop on Combinatorial Optimization (Bonn, 1980). Ann. Discrete Math. 16, 261–280 (1982)
Schrijver, A.: Combinatorial Optimization: Polyhedra and Efficiency, vol. 3. Springer, Berlin (2003)
Szegő, L.: Note on covering intersecting set-systems by digraphs. Discrete Math. 234, 187–189 (2001)
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This paper is dedicated to my son, Pedro Rey.
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Leston-Rey, M., Lee, O. Stronger bounds and faster algorithms for packing in generalized kernel systems. Math. Program. 159, 31–80 (2016). https://doi.org/10.1007/s10107-015-0948-4
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DOI: https://doi.org/10.1007/s10107-015-0948-4