Abstract
We introduce the simple extension complexity of a polytope \(P\) as the smallest number of facets of any simple (i.e., non-degenerate in the sense of linear programming) polytope which can be projected onto \(P\). We devise a combinatorial method to establish lower bounds on the simple extension complexity and show for several polytopes that they have large simple extension complexities. These examples include both the spanning tree and the perfect matching polytopes of complete graphs, uncapacitated flow polytopes for non-trivially decomposable directed acyclic graphs, hypersimplices, and random 0/1-polytopes with vertex numbers within a certain range. On our way to obtain the result on perfect matching polytopes we generalize a result of Padberg and Rao’s on the adjacency structures of those polytopes. In addition to the material in the extended abstract (Kaibel and Walter in Integer programming and combinatorial optimization. Lecture Notes in Computer Science, vol 8494. Springer, Berlin, 2014) we include omitted proofs, supporting figures, and an analysis of known upper bounding techniques.
Similar content being viewed by others
References
Avis, D., Tiwary, H.R.: On the extension complexity of combinatorial polytopes. In: Fomin, F.V., Freivalds, R., Kwiatkowska, M.Z., Peleg, D. (eds.) Automata, Languages, and Programming, volume 7965 of Lecture Notes in Computer Science, pp. 57–68. Springer, Berlin (2013)
Balas, E.: Disjunctive Programming: Properties of the Convex Hull of Feasible Points. MSRR 348, Carnegie Mellon University, Pittsburg, PA (1974)
Balas, E.: Disjunctive programming. In: Johnson, E.L., Hammer, P.L., Korte, B.H. (eds.) Discrete Optimization II. Annals of Discrete Mathematics, vol. 5, pp. 3–51. Elsevier (1979). http://dx.doi.org/10.1016/S0167-5060(08)70342-X
Bienstock, D.: Approximate formulations for 0–1 knapsack sets. Oper. Res. Lett. 36(3), 317–320 (2008)
Carr, R.D., Konjevod, G.: Polyhedral combinatorics. In: Greenberg, H.J. (ed.) Tutorials on Emerging Methodologies and Applications in Operations Research volume 76 of International Series in Operations Research and Management Science, chapter 2, pp. 1–46. Springer, Berlin (2005)
Chvátal, V.: On certain polytopes associated with graphs. J. Combin. Theory Ser. B 18(2), 138–154 (1975)
Dantzig, G.B.: Linear Programming and Extensions. Princeton Landmarks in Mathematics and Physics. Princeton University Press, Princeton (1963)
Fiorini, S., Kaibel, V., Pashkovich, K., Theis, D.O.: Combinatorial bounds on nonnegative rank and extended formulations. Discrete Math. 313(1), 67–83 (2013)
Fiorini, S., Massar, S., Pokutta, S., Tiwary, H.R., de Wolf, R.: Linear vs. semidefinite extended formulations: exponential separation and strong lower bounds. In: Karloff, H.J., Pitassi, T. (eds.) STOC, pp. 95–106. ACM, New York (2012)
Gallo, G., Sodini, C.: Extreme points and adjacency relationship in the flow polytope. Calcolo 15, 277–288 (1978). doi:10.1007/BF02575918
Gillmann, R.: 0/1-Polytopes typical and extremal properties. PhD thesis, Technische Universität, Berlin (2007)
Goemans, M.: Smallest compact formulation for the permutahedron. http://www-math.mit.edu/goemans/publ.html (2009)
Kaibel, V., Pashkovich, K.: Constructing extended formulations from reflection relations. In: Günlük, O., Woeginger, G. (eds.) Integer Programming and Combinatorial Optimization. Proceedings of IPCO XV, New York, NY volume 6655 of Lecture Notes in Computer Science, pp. 287–300. Springer, Berlin (2011)
Kaibel, V., Pashkovich, K., Theis, D.O.: Symmetry matters for sizes of extended formulations. SIAM J. Discrete Math. 26(3), 1361–1382 (2012)
Kaibel, V., Walter, M.: Simple extensions of polytopes. In: Lee, J., Vygen, J. (eds.) Integer Programming and Combinatorial Optimization. Proceedings of IPCO XVII, Bonn, volume 8494 of Lecture Notes in Computer Science. Springer, Berlin (2014)
Kipp Martin, R.: Using separation algorithms to generate mixed integer model reformulations. Oper. Res. Lett. 10(3), 119–128 (1991)
Padberg, M.W., Rao, M.R.: The travelling salesman problem and a class of polyhedra of diameter two. Math. Program. 7, 32–45 (1974). doi:10.1007/BF01585502
Pashkovich, K.: Tight lower bounds on the sizes of symmetric extensions of permutahedra and similar results. Math. Oper. Res. 39(4), 1330–1339 (2014)
Pokutta, S., Van Vyve, M.: A note on the extension complexity of the knapsack polytope. Oper. Res. Lett. 41(4), 347–350 (2013)
Rothvoss, T.: Some 0/1 polytopes need exponential size extended formulations. Math. Program., Ser. A 142, 255–268 (2013)
Rothvoss, T.: The matching polytope has exponential extension complexity. In: Proceedings of the 46th Annual ACM Symposium on Theory of Computing, STOC’14, New York, NY, USA, pp. 263–272. ACM, New York (2014)
Santos, F.: A counterexample to the hirsch conjecture. Ann. Math. 176(1), 383–412 (2012)
Schrijver, A.: Combinatorial Optimization—Polyhedra and Efficiency. Springer, Berlin (2003)
Yannakakis, M.: Expressing combinatorial optimization problems by linear programs. J. Comput. Syst. Sci. 43(3), 441–466 (1991)
Ziegler, G.M.: Lectures on Polytopes (Graduate Texts in Mathematics). Springer, Berlin (2001)
Acknowledgments
We are greatful to the referees whose comments lead to significant improvements in the presentation of the material.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Kaibel, V., Walter, M. Simple extensions of polytopes. Math. Program. 154, 381–406 (2015). https://doi.org/10.1007/s10107-015-0885-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10107-015-0885-2