Skip to main content
Log in

Counting Polygon Triangulations is Hard

  • Published:
Discrete & Computational Geometry Aims and scope Submit manuscript

Abstract

We prove that it is \(\#{\mathsf {P}}\)-complete to count the triangulations of a (non-simple) polygon.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11

Similar content being viewed by others

Notes

  1. See Sect. 2.2 for the definitions of \(\#{\mathsf {P}}\) and \(\#{\mathsf {P}}\)-completeness.

References

  1. Aichholzer, O., Alvarez, V., Hackl, T., Pilz, A., Speckmann, B., Vogtenhuber, B.: An improved lower bound on the minimum number of triangulations. In: 32nd International Symposium on Computational Geometry. Leibniz Int. Proc. Inform., vol. 51, # 7. Leibniz-Zent. Inform., Wadern (2016)

  2. Aichholzer, O., Hackl, T., Huemer, C., Hurtado, F., Krasser, H., Vogtenhuber, B.: On the number of plane geometric graphs. Graphs Comb. 23(suppl. 1), 67–84 (2007)

    Article  MathSciNet  MATH  Google Scholar 

  3. Aichholzer, O., Hurtado, F., Noy, M.: A lower bound on the number of triangulations of planar point sets. Comput. Geom. 29(2), 135–145 (2004)

    Article  MathSciNet  MATH  Google Scholar 

  4. Aichholzer, O., Orden, D., Santos, F., Speckmann, B.: On the number of pseudo-triangulations of certain point sets. J. Comb. Theory Ser. A 115(2), 254–278 (2008)

    Article  MathSciNet  MATH  Google Scholar 

  5. Alvarez, V., Bringmann, K., Curticapean, R., Ray, S.: Counting triangulations and other crossing-free structures via onion layers. Discrete Comput. Geom. 53(4), 675–690 (2015)

    Article  MathSciNet  MATH  Google Scholar 

  6. Alvarez, V., Bringmann, K., Ray, S., Seidel, R.: Counting triangulations and other crossing-free structures approximately. Comput. Geom. 48(5), 386–397 (2015)

    Article  MathSciNet  MATH  Google Scholar 

  7. Alvarez, V., Seidel, R.: A simple aggregative algorithm for counting triangulations of planar point sets and related problems. In: 29th Annual Symposium on Computational Geometry (Rio de Janeiro 2013), pp. 1–8. ACM, New York (2013)

  8. Anclin, E.E.: An upper bound for the number of planar lattice triangulations. J. Comb. Theory Ser. A 103(2), 383–386 (2003)

    Article  MathSciNet  MATH  Google Scholar 

  9. Asano, Tak., Asano, Tet., Imai, H.: Partitioning a polygonal region into trapezoids. J. Assoc. Comput. Mach. 33(2), 290–312 (1986)

  10. Asinowski, A., Rote, G.: Point sets with many non-crossing perfect matchings. Comput. Geom. 68, 7–33 (2018)

    Article  MathSciNet  MATH  Google Scholar 

  11. Bern, M., Eppstein, D.: Mesh generation and optimal triangulation. In: Computing in Euclidean Geometry. Lecture Notes Ser. Comput., vol. 1, pp. 23–90. World Scientific, River Edge (1992)

  12. Bespamyatnikh, S.: An efficient algorithm for enumeration of triangulations. Comput. Geom. 23(3), 271–279 (2002)

    Article  MathSciNet  MATH  Google Scholar 

  13. Brönnimann, H., Kettner, L., Pocchiola, M., Snoeyink, J.: Counting and enumerating pointed pseudotriangulations with the greedy flip algorithm. SIAM J. Comput. 36(3), 721–739 (2006)

    Article  MathSciNet  MATH  Google Scholar 

  14. Chalopin, J., Gonçalves, D.: Every planar graph is the intersection graph of segments in the plane: extended abstract. In: 41st Annual ACM Symposium on Theory of Computing (Bethesda 2009), pp. 631–638. ACM, New York (2009)

  15. Ding, Q., Qian, J., Tsang, W., Wang, C.: Randomly generating triangulations of a simple polygon. In: Computing and Combinatorics (Kunming 2005). Lecture Notes in Computer Science, vol. 3595, pp. 471–480. Springer, Berlin (2005)

  16. Dittmer, S., Pak, I.: Counting linear extensions of restricted posets (2018). https://arxiv.org/abs/1802.06312

  17. Dumitrescu, A., Schulz, A., Sheffer, A., Tóth, C.D.: Bounds on the maximum multiplicity of some common geometric graphs. SIAM J. Discrete Math. 27(2), 802–826 (2013)

    Article  MathSciNet  MATH  Google Scholar 

  18. Dyer, M., Goldberg, L.A., Paterson, M.: On counting homomorphisms to directed acyclic graphs. J. ACM 54(6), # 27 (2007)

  19. Eppstein, D.: Forbidden Configurations in Discrete Geometry. Cambridge University Press, Cambridge (2018)

    Book  MATH  Google Scholar 

  20. Epstein, P., Sack, J.-R.: Generating triangulations at random. ACM Trans. Model. Comput. Simul. 4(3), 267–278 (1994)

    Article  MATH  Google Scholar 

  21. Flajolet, P., Noy, M.: Analytic combinatorics of non-crossing configurations. Discrete Math. 204(1–3), 203–229 (1999)

    Article  MathSciNet  MATH  Google Scholar 

  22. de Fraysseix, H., Pach, J., Pollack, R.: How to draw a planar graph on a grid. Combinatorica 10(1), 41–51 (1990)

    Article  MathSciNet  MATH  Google Scholar 

  23. García, A., Noy, M., Tejel, J.: Lower bounds on the number of crossing-free subgraphs of \(K_N\). Comput. Geom. 16(4), 211–221 (2000)

    Article  MathSciNet  MATH  Google Scholar 

  24. Hurtado, F., Noy, M., Urrutia, J.: Flipping edges in triangulations. Discrete Comput. Geom. 22(3), 333–346 (1999)

    Article  MathSciNet  MATH  Google Scholar 

  25. Jaeger, F., Vertigan, D.L., Welsh, D.J.A.: On the computational complexity of the Jones and Tutte polynomials. Math. Proc. Camb. Philos. Soc. 108(1), 35–53 (1990)

    Article  MathSciNet  MATH  Google Scholar 

  26. Jarník, V.: Über die Gitterpunkte auf konvexen Kurven. Math. Z. 24(1), 500–518 (1926)

    Article  MathSciNet  MATH  Google Scholar 

  27. Kaibel, V., Ziegler, G.M.: Counting lattice triangulations. In: Surveys in Combinatorics 2003. London Mathematical Society Lecture Note Series, vol. 307, pp. 277–307. Cambridge University Press, Cambridge (2003)

  28. Kamousi, P., Suri, S.: Stochastic minimum spanning trees and related problems. In: ANALCO11—Workshop on Analytic Algorithmics and Combinatorics (San Francisco 2011), pp. 107–116. SIAM, Philadelphia (2011)

  29. Kant, G., Bodlaender, H.L.: Triangulating planar graphs while minimizing the maximum degree. Inform. Comput. 135(1), 1–14 (1997)

    Article  MathSciNet  MATH  Google Scholar 

  30. Karpinski, M., Lingas, A., Sledneu, D.: A QPTAS for the base of the number of crossing-free structures on a planar point set. Theoret. Comput. Sci. 711, 56–65 (2018)

    Article  MathSciNet  MATH  Google Scholar 

  31. Linial, N.: Hard enumeration problems in geometry and combinatorics. SIAM J. Algebraic Discrete Methods 7(2), 331–335 (1986)

    Article  MathSciNet  MATH  Google Scholar 

  32. Lubiw, A.: Decomposing polygonal regions into convex quadrilaterals. In: 1st Annual Symposium on Computational Geometry (Baltimore 1985), pp. 97–106. ACM, New York (1985)

  33. Marx, D., Miltzow, T.: Peeling and nibbling the cactus: subexponential-time algorithms for counting triangulations and related problems. In: 32nd International Symposium on Computational Geometry. Leibniz Int. Proc. Inform., vol. 51, # 52. Leibniz-Zent. Inform., Wadern (2016)

  34. Pilz, A., Seara, C.: Convex quadrangulations of bichromatic point sets. In: 33rd European Workshop on Computational Geometry (Malmö 2017), pp. 77–80. http://csconferences.mah.se/eurocg2017/proceedings.pdf

  35. Ray, S., Seidel, R.: A simple and less slow method for counting triangulations and for related problems. In: 20th European Workshop on Computational Geometry (Seville 2004). http://www.eurocg.org/www.us.es/ewcg04/Articulos/seidel-s.ps

  36. Santos, F., Seidel, R.: A better upper bound on the number of triangulations of a planar point set. J. Combin. Theory Ser. A 102(1), 186–193 (2003)

    Article  MathSciNet  MATH  Google Scholar 

  37. Scheinerman, E.R.: Intersection Classes and Multiple Intersection Parameters of Graphs. PhD thesis, Princeton University (1984)

  38. Schnyder, W.: Embedding planar graphs on the grid. In: 1st Annual ACM-SIAM Symposium on Discrete Algorithms (San Francisco 1990), pp. 138–148. SIAM, Philadelphia (1990)

  39. Seidel, R.: On the number of triangulations of planar point sets. Combinatorica 18(2), 297–299 (1998)

    Article  MathSciNet  MATH  Google Scholar 

  40. Sharir, M., Sheffer, A.: Counting triangulations of planar point sets. Electron. J. Combin. 18(1), # 70 (2011)

  41. Sharir, M., Sheffer, A., Welzl, E.: Counting plane graphs: perfect matchings, spanning cycles, and Kasteleyn’s technique. J. Combin. Theory Ser. A 120(4), 777–794 (2013)

    Article  MathSciNet  MATH  Google Scholar 

  42. Sharir, M., Welzl, E.: On the number of crossing-free matchings, cycles, and partitions. SIAM J. Comput. 36(3), 695–720 (2006)

    Article  MathSciNet  MATH  Google Scholar 

  43. Vadhan, S.P.: The complexity of counting in sparse, regular, and planar graphs. SIAM J. Comput. 31(2), 398–427 (2001)

    Article  MathSciNet  MATH  Google Scholar 

  44. Valiant, L.G.: The complexity of computing the permanent. Theor. Comput. Sci. 8(2), 189–201 (1979)

    Article  MathSciNet  MATH  Google Scholar 

  45. Wettstein, M.: Counting and enumerating crossing-free geometric graphs. J. Comput. Geom. 8(1), 47–77 (2017)

    MathSciNet  MATH  Google Scholar 

  46. Xia, M., Zhang, P., Zhao, W.: Computational complexity of counting problems on \(3\)-regular planar graphs. Theor. Comput. Sci. 384(1), 111–125 (2007)

    Article  MathSciNet  MATH  Google Scholar 

Download references

Acknowledgements

A preliminary version of this paper appeared in the Proceedings of the 2019 International Symposium on Computational Geometry. This work was supported in part by the US National Science Foundation under Grants CCF-1618301 and CCF-1616248.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to David Eppstein.

Additional information

Editor in Charge: Kenneth Clarkson

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Eppstein, D. Counting Polygon Triangulations is Hard. Discrete Comput Geom 64, 1210–1234 (2020). https://doi.org/10.1007/s00454-020-00251-7

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00454-020-00251-7

Keywords

Mathematics Subject Classification

Navigation