Abstract
We solve a problem in the combinatorics of polyhedra motivated by the network simplex method. We show that the Hirsch conjecture holds for the diameter of the graphs of all network-flow polytopes, in particular the diameter of a network-flow polytope for a network with n nodes and m arcs is never more than \(m+n-1\). A key step to prove this is to show the same result for classical transportation polytopes.















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S. Borgwardt gratefully acknowledges support from the Alexander-von-Humboldt Foundation. J. A. De Loera is grateful for the support received through NSF Grant DMS-1522158. J. A. De Loera and E. Finhold gratefully acknowledge the support from the Hausdorff Research Institute for Mathematics (HIM) in Bonn.
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Borgwardt, S., De Loera, J.A. & Finhold, E. The diameters of network-flow polytopes satisfy the Hirsch conjecture. Math. Program. 171, 283–309 (2018). https://doi.org/10.1007/s10107-017-1176-x
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DOI: https://doi.org/10.1007/s10107-017-1176-x
Keywords
- Combinatorial diameter
- Diameter of graphs of polyhedra
- Hirsch conjecture
- Simplex method
- Network simplex method
- Network-flow polytopes
- Transportation polytopes