Skip to main content
Log in

Coxeter-biCatalan combinatorics

  • Published:
Journal of Algebraic Combinatorics Aims and scope Submit manuscript

Abstract

We pose counting problems related to the various settings for Coxeter-Catalan combinatorics (noncrossing, nonnesting, clusters, Cambrian). Each problem is to count “twin” pairs of objects from a corresponding problem in Coxeter-Catalan combinatorics. We show that the problems all have the same answer, and, for a given finite Coxeter group W, we call the common solution to these problems the W-biCatalan number. We compute the W-biCatalan number for all W and take the first steps in the study of Coxeter-biCatalan combinatorics.

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

Similar content being viewed by others

References

  1. Athanasiadis, C.A.: Generalized Catalan numbers, Weyl groups and arrangements of hyperplanes. Bull. Lond. Math. Soc. 36(3), 294–302 (2004)

    Article  MathSciNet  MATH  Google Scholar 

  2. Athanasiadis, C.A., Brady, T., McCammond, J., Watt, C.: \(h\)-Vectors of generalized associahedra and noncrossing partitions. Int. Math. Res. Not. Art. ID 69705 (2006)

  3. Athanasiadis, C.A., Savvidou, C.: The local \(h\)-vector of the cluster subdivision of a simplex. Sém. Lothar. Combin. 66, Art. B66c (2011/12)

  4. Athanasiadis, C.A., Tzanaki, E.: On the enumeration of positive cells in generalized cluster complexes and Catalan hyperplane arrangements. J. Algebr. Combin. 23(4), 355–375 (2006)

    Article  MathSciNet  MATH  Google Scholar 

  5. Armstrong, D.: Generalized noncrossing partitions and combinatorics of coxeter groups. Mem. Am. Math. Soc. 202(949) (2009)

  6. Baxter, G.: On fixed points of the composite of commuting functions. Proc. Am. Math. Soc. 15, 851–855 (1964)

    Article  MathSciNet  MATH  Google Scholar 

  7. Björner, A., Brenti, F.: The Combinatorics of Coxeter Groups. Graduate Texts in Mathematics, vol. 231. Springer, New York (2005)

  8. Bousquet-Mélou, M., Claesson, A., Anders, M.Dukes, Kitaev, S.: \((2+2)\)-free posets, ascent sequences and pattern avoiding permutations. J. Combin. Theory Ser. A 117(7), 884–909 (2010)

    Article  MathSciNet  MATH  Google Scholar 

  9. Brady, T., Watt, C.: From permutahedron to associahedron. Proc. Edinb. Math. Soc. (2) 53(2), 299–310 (2010)

    Article  MathSciNet  MATH  Google Scholar 

  10. Chapoton, F., Fomin, S., Zelevinsky, A.: Polytopal realizations of generalized associahedra. Canad. Math. Bull. 45(4), 537–566 (2002)

    Article  MathSciNet  MATH  Google Scholar 

  11. Châtel, G., Pilaud, V.: Cambrian Hopf algebras. Adv. Math. 311, 598–633 (2017)

    Article  MathSciNet  MATH  Google Scholar 

  12. Chung, F.R.K., Graham, R.L., Hoggatt Jr., V.E., Kleiman, M.: The number of Baxter permutations. J. Combin. Theory Ser. A 24(3), 382–394 (1978)

    Article  MathSciNet  MATH  Google Scholar 

  13. Demonet, L., Iyama, O., Reading, N., Reiten, I., Thomas, H.: Lattice theory of torsion classes. (In preparation)

  14. Deutsch, E., Shapiro, L.: A survey of the Fine numbers. Discrete Math. 241(1–3), 241–265 (2001)

    Article  MathSciNet  MATH  Google Scholar 

  15. Dilks, K.: Involutions on Baxter Objects. Preprint, 2014. (arXiv:1402.2961)

  16. Dulucq, S., Guibert, O.: Stack words, standard tableaux and Baxter permutations. Discrete Math. 157(1–3), 91–106 (1996)

    Article  MathSciNet  MATH  Google Scholar 

  17. Felsner, S., Fusy, É., Noy, M., Orden, D.: Bijections for Baxter families and related objects. J. Combin. Theory Ser. A 118(3), 993–1020 (2011)

    Article  MathSciNet  MATH  Google Scholar 

  18. Fomin, S., Reading, N.: Root systems and generalized associahedra. IAS/Park City Math. Ser. 13, 63–131

  19. Fomin, S., Reading, N.: Generalized cluster complexes and Coxeter combinatorics. Int. Math. Res. Not. 2005(44), 2709–2757 (2005)

  20. Fomin, S., Zelevinsky, A.: \(Y\)-systems and generalized associahedra. Ann. of Math. (2) 158(3), 977–1018 (2003)

    Article  MathSciNet  MATH  Google Scholar 

  21. Fomin, S., Zelevinsky, A.: Cluster algebras II: finite type classification. Invent. Math. 154, 63–121 (2003)

    Article  MathSciNet  MATH  Google Scholar 

  22. Giraudo, S.: Algebraic and combinatorial structures on pairs of twin binary trees. J. Algebra 360, 115–157 (2012)

    Article  MathSciNet  MATH  Google Scholar 

  23. Haiman, M.D.: Conjectures on the quotient ring by diagonal invariants. J. Algebr. Combin. 3(1), 17–76 (1994)

    Article  MathSciNet  MATH  Google Scholar 

  24. Hohlweg, C., Lange, C.E.M.C.: Realizations of the associahedron and cyclohedron. Discrete Comput. Geom. 37(4), 517–543 (2007)

    Article  MathSciNet  MATH  Google Scholar 

  25. Hohlweg, C., Lange, C., Thomas, H.: Permutahedra and generalized associahedra. Adv. Math. 226(1), 608–640 (2011)

    Article  MathSciNet  MATH  Google Scholar 

  26. Law, S.E., Reading, N.: The Hopf algebra of diagonal rectangulations. J. Combin. Theory Ser. A 119(3), 788–824 (2012)

    Article  MathSciNet  MATH  Google Scholar 

  27. Marsh, R., Reineke, M., Zelevinsky, A.: Generalized associahedra via quiver representations. Trans. Am. Math. Soc. 355(10), 4171–4186 (2003)

    Article  MathSciNet  MATH  Google Scholar 

  28. Panyushev, D.I.: \(ad\)-Nilpotent ideals of a Borel subalgebra: generators and duality. J. Algebra 274(2), 822–846 (2004)

    Article  MathSciNet  MATH  Google Scholar 

  29. Postnikov, A., Reiner, V., Williams, L.: Faces of generalized permutohedra. Doc. Math. 13, 207–273 (2008)

    MathSciNet  MATH  Google Scholar 

  30. Reading, N.: Lattice congruences of the weak order. Order 21(4), 315–344 (2004)

    Article  MathSciNet  MATH  Google Scholar 

  31. Reading, N.: Lattice congruences, fans and Hopf algebras. J. Combin. Theory Ser. A 110(2), 237–273 (2005)

    Article  MathSciNet  MATH  Google Scholar 

  32. Reading, N.: Cambrian lattices. Adv. Math. 205(2), 313–353 (2006)

    Article  MathSciNet  MATH  Google Scholar 

  33. Reading, N.: Clusters, Coxeter-sortable elements and noncrossing partitions. Trans. Am. Math. Soc. 359(12), 5931–5958 (2007)

    Article  MathSciNet  MATH  Google Scholar 

  34. Reading, N.: Sortable elements and Cambrian lattices. Algebra Univ. 56(3–4), 411–437 (2007)

    Article  MathSciNet  MATH  Google Scholar 

  35. Reading, N.: Noncrossing partitions and the shard intersection order. J. Algebr. Combin. 33(4), 483–530 (2011)

    Article  MathSciNet  MATH  Google Scholar 

  36. Reading, N.: Noncrossing arc diagrams and canonical join representations. SIAM J. Discrete Math. 29(2), 736–750 (2015)

    Article  MathSciNet  MATH  Google Scholar 

  37. Reading, N.: Lattice theory of the poset of regions. In: Grätzer, G., Wehrung, F. (eds.) Lattice Theory: Special Topics and Applications, Vol. 2. Birkhäuser, Cham (2016)

  38. Reading, N., Speyer, D.E.: Cambrian fans. J. Eur. Math. Soc. JEMS. 11(2), 407–447 (2006)

    MathSciNet  MATH  Google Scholar 

  39. Reading, N., Speyer, D.E.: Sortable elements in infinite Coxeter groups Trans. Am. Math. Soc. 363(2), 699–761 (2011)

    Article  MATH  Google Scholar 

  40. Reading, N., Speyer, D.E.: Cambrian frameworks for cluster algebras of affine type. Trans. Amer. Math. Soc (to appear)

  41. Salvy, B., Zimmermann, P.: GFUN: a Maple package for the manipulation of generating and holonomic functions in one variable. ACM Trans. Math. Softw. 20(2), 163–177 (1994)

    Article  MATH  Google Scholar 

  42. Sommers, E.N.: \(B\)-stable ideals in the nilradical of a Borel subalgebra. Canad. Math. Bull. 48(3), 460–472 (2005)

    Article  MathSciNet  MATH  Google Scholar 

  43. Stanley, R.P.: Subdivisions and local h-vectors. J. Am. Math. Soc. 5, 805–851 (1992)

    MathSciNet  MATH  Google Scholar 

  44. Stanley, R.P.: Enumerative combinatorics. Vol. 1, second edition. In: Cambridge Studies in Advanced Mathematics vol. 49. Cambridge University Press, Cambridge (2012)

  45. Stembridge, J.: Maple packages for symmetric functions, posets, root systems, and finite Coxeter groups. http://www.math.lsa.umich.edu/~jrs/maple.html

  46. Stembridge, J.: Quasi-minuscule quotients and reduced words for reflections. J. Algebr. Combin. 13(3), 275–293 (2001)

    Article  MathSciNet  MATH  Google Scholar 

  47. The Online Encyclopedia of Integer Sequences (https://oeis.org)

  48. West, J.: Personal communication (2006)

  49. Williams, N.: Cataland. Ph.D. Thesis, University of Minnesota (2013)

  50. Yang, S., Zelevinsky, A.: Cluster algebras of finite type via Coxeter elements and principal minors. Transform. Groups 13(3–4), 855–895 (2008)

    Article  MathSciNet  MATH  Google Scholar 

  51. Ziegler, G.: Lectures on polytopes. Graduate Texts in Mathematics, vol. 152. Springer, New York (1995)

    Book  Google Scholar 

Download references

Acknowledgements

Bruno Salvy’s and Paul Zimmermann’s package GFUN [41] was helpful in guessing a formula for the \(D_n\)-Catalan number. John Stembridge’s packages posets and coxeter/weyl [45] were invaluable in counting antichains in the doubled root poset, in checking the distributivity of the doubled root poset, and in verifying the simpliciality of the bipartite biCambrian fan. The authors thank Christos Athanasiadis, Christophe Hohlweg, Richard Stanley, Salvatore Stella, and Bernd Sturmfels for helpful suggestions and questions.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Nathan Reading.

Additional information

Emily Barnard was supported in part by NSF Grants DMS-0943855, DMS-1101568, and DMS-1500949. Nathan Reading was supported in part by NSF Grants DMS-1101568 and DMS-1500949.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Barnard, E., Reading, N. Coxeter-biCatalan combinatorics. J Algebr Comb 47, 241–300 (2018). https://doi.org/10.1007/s10801-017-0775-1

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10801-017-0775-1

Keywords

Navigation