Abstract
We present a general model for set systems to be independence families with respect to set families which determine classes of proper weight functions on a ground set. Within this model, matroids arise from a natural subclass and can be characterized by the optimality of the greedy algorithm. This model includes and extends many of the models for generalized matroid-type greedy algorithms proposed in the literature and, in particular, integral polymatroids. We discuss the relationship between these general matroids and classical matroids and provide a Dilworth embedding that allows us to represent matroids with underlying partial order structures within classical matroids. Whether a similar representation is possible for matroids on convex geometries is an open question.
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Barnabei, M., Nicoletti, G., Pezzoli, L.: Matroids on partially ordered sets. Adv. Appl. Math. 21, 78–112 (1998)
Crawley, P., Dilworth, R.P.: Algebraic Theory of Lattices. Prentice-Hall, Englewood Cliffs (1973)
Dietrich, B.L., Hoffman, A.J.: On greedy algorithms, partially ordered sets, and submodular functions. IBM J. Res. Dev. 47, 25–30 (2003)
Dunstan, F.D.J., Ingleton, A.W., Welsh, D.J.A.: Supermatroids. In: Proceedings of the Conference on Combinatorial Mathematics, Mathematical Institute Oxford, 1972, Combinatorics (1972), 72–122
Edelman, P., Jamison, R.E.: The theory of convex geometries. Geom. Dedic. 19, 247–270 (1985)
Edmonds, J.: Submodular functions, matroids, and certain polyhedra. In: Guy, R., et al. (eds.) Combinatorial Structures and Their Applications, pp. 69–87. Gordon and Breach, New York (1970)
Edmonds, J.: Matroids and the greedy algorithm. Math. Program. 1, 127–136 (1971)
Faigle, U.: The greedy algorithm for partially ordered sets. Discrete Math. 28, 153–159 (1979)
Faigle, U.: Geometries on partially ordered sets. J. Comb. Theory B 28, 26–51 (1980)
Faigle, U.: On supermatroids with submodular rank functions. In: Algebraic Methods in Graph Theory I. Colloq. Math. Soc. J. Bolyai, vol.25, pp.149–158 (1981)
Faigle, U.: On ordered languages and the optimization of linear functions by greedy algorithms. J. Assoc. Comput. Mach. 32, 861–870 (1985)
Faigle, U.: Matroids in combinatorial optimization. In: White, N.(eds) Combinatorial Geometries, Encyclopedia of Math. and Its Applications, vol.29, pp. 161–210. Cambridge University Press, New York (1987)
Faigle, U., Kern, W.: Submodular linear programs on forests. Math. Program. 72, 195–206 (1996)
Faigle, U., Kern, W.: On the core of ordered submodular cost games. Math. Program. 87, 483–489 (2000)
Faigle, U., Kern, W.: An order-theoretic framework for the greedy algorithm with applications to the core and Weber set of cooperative games. Order 17, 353–375 (2000)
Fujishige, S.: Dual greedy polyhedra, choice functions, and abstract convex geometries. Discrete Optim. 1, 41–49 (2004)
Fujishige, S.: Submodular functions and optimization. In: Annals of Discrete Mathematics, vol.58, 2nd edn (2005)
Fujishige, S., Koshevoy, G.A., Sano, Y.: Matroids on convex geometries (cg-matroids). Discrete Math. 307, 1936–1950 (2007)
Gale, D.: Optimal assignments in an ordered set: an application of matroid theory. J. Comb. Theory 4, 176–180 (1968)
Hoffman, A.J.: On simple linear programming problems. In: Klee, V. (ed.) Convexity: Proceedings of the Seventh Symposium in Pure Mathematics, pp.317–327. American Mathematical Society (1963)
Korte, B., Lovász, L., Schrader, R.: Greedoids. In: Algorithms and Combinatorics, vol.4. Springer, Heidelberg (1991)
Krüger, U.: Structural aspects of ordered polymatroids. Discrete Appl. Math. 99, 125–148 (2000)
Monge, G.: Déblai et Remblai. Mem. de l’Académie des Science (1781)
Queyranne, M., Spieksma, F., Tardella, F.: A general class of greedily solvable linear programs. Math. Oper. Res. 23, 892–908 (1998)
Sano, Y.: Rank functions of strict cg-matroids. RIMS Preprint No.1560, Research Institute for Mathematical Sciences, Kyoto University (2006)
Sano, Y.: The greedy algorithm for strict cg-matroids. RIMS Preprint No.1581, Research Institute for Mathematical Sciences, Kyoto University (2007)
Shenmaier, V.V.: A greedy algorithm for some classes of integer programs. Discrete Appl. Math. 133, 93–101 (2004)
Tardos, E.: An intersection theorem for supermatroids. J. Comb. Theory B 50, 150–159 (1990)
Welsh, D.J.A.: Matroid Theory. Academic Press, London (1976)
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S. Fujishige’s research was supported by a Grant-in-Aid for Scientific Research of the Ministry of Education, Culture, Sports, Science and Technology of Japan.
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Faigle, U., Fujishige, S. A general model for matroids and the greedy algorithm. Math. Program. 119, 353–369 (2009). https://doi.org/10.1007/s10107-008-0213-1
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DOI: https://doi.org/10.1007/s10107-008-0213-1