×

Some instances of homomesy among ideals of posets. (English) Zbl 1509.05183

Summary: Given a permutation \(\tau\) defined on a set of combinatorial objects \(S\), together with some statistic \(f:S\rightarrow \mathbb{R} \), we say that the triple \(\langle S, \tau,f \rangle\) exhibits homomesy if \(f\) has the same average along all orbits of \(\tau\) in \(S\). This phenomenon was observed by D. I. Panyushev [Eur. J. Comb. 30, No. 2, 586–594 (2009; Zbl 1165.06001)] and later studied, named and extended by J. Propp and T. Roby [Electron. J. Comb. 22, No. 3, Research Paper P3.4, 29 p. (2015; Zbl 1319.05151)]. Propp and Roby studied homomesy in the set of order ideals in the product of two chains, with two well known permutations, rowmotion and promotion, the statistic being the size of the order ideal. In this paper we extend their results to generalized rowmotion and promotion, together with a wider class of statistics in the product of two chains. Moreover, we derive similar results in other simply described posets. We believe that the framework we set up here can be fruitful in demonstrating homomesy results in order ideals of broader classes of posets.

MSC:

05E18 Group actions on combinatorial structures
06A11 Algebraic aspects of posets
06A07 Combinatorics of partially ordered sets

References:

[1] D. Armstrong, C. Stump and H. Thomas,A Uniform Bijection Between Nonnesting and Noncrossing Partitions(August 2013), Transactions of American Mathematical Society, Vol. 365, No. 8, Pages 4121-4151. · Zbl 1271.05011
[2] J. Bloom, O. Pechenik and D. Saracino,Proofs and Generalizations of a Homomesy Conjecture of Propp and Roby(2016), Discrete Mathematics, Vol. 339, Issue 1, Pages 194-206. · Zbl 1322.05136
[3] A. Brouwer and A. Schrijver,On the Period of an Operator Defined on Antichains (1974), Stichting Mathematisch Centrum, Zuivere Wiskunde (ZW 24/74): 1-13. · Zbl 0282.06003
[4] P. Cameron and D. Fon-Der-Flaass,Orbits of Antichains Revisited(1995), European Journal of Combinatorics, Vol. 16, Issue 6, Pages 545-554. · Zbl 0831.06001
[5] M. Chan, S. Haddadan, S. Hopkins, and L. Moci,The Expected Jaggedness of Order Ideals,(2017), SIGMA Forum of Mathematics, Vol. 5, Issue 9. · Zbl 1358.05313
[6] K. Dilks, J. Striker, C. Vorland,Rowmotion and Increasing Labeling Promotion (2019), Journal of Combinatorial Theory, Series A, Vol. 164, Pages 72-108. · Zbl 1407.05245
[7] D. Einstein, M. Farber, E. Gunawan, M. Joseph, M. Macauley, J. Propp, and S. Rubinstein-Salzedo,Noncrossing Partitions, Toggles, and Homomesies.(2016), DMTCS Proceedings of Discrete Mathematics and Theoretical Computer Science, Pages 419-430. · Zbl 1440.05036
[8] D. Einstein and J. Propp,Piecewise-linear and Birational Toggling,(2014), Discrete Mathematics & Theoretical Computer Science (2014), Pages 513-524. · Zbl 1394.06005
[9] S. Hopkins and I. Zhang,A Note on Statistical Averages for Oscillating Tableaux, (2015), The Electronic Journal of Combinatorics, Vol. 22, Issue 2, #P2.48. · Zbl 1327.05024
[10] D. Panyushev,On Orbits of Antichains with Positive Roots(2009), European Journal of Combinatorics, Vol. 30, Issue 2, Pages 586-594. · Zbl 1165.06001
[11] G. P´olya,Kombinatorische Anzahlbestimmungen fur Gruppen, Graphen und chemische Verbindungen(1937), Acta Mathematica, Vol. 68 (1), Pages 145-254. · JFM 63.0547.04
[12] J. Bernstein, J. Striker, C. Vorland,P-strict promotion and piecewise linear rowmotion, with applications to tableaux of many flavors,arXiv:2012.12219.
[13] M. Joseph and T. Roby,Birational and non-commutative lifts of anti-chain toggling and row-motion, Algebraic Combinatorics, Vol. 3(4) (2020), Pages. 955-984. arXiv:1909.09658. · Zbl 1448.05226
[14] J. Propp and T. Roby,Homomesy in Products of Two Chains(2015), DMTCS Proceedings, The Electronic Journal of Combinatorics, Vol. 22, Issue 3, #P3.4. · Zbl 1319.05151
[15] D. B. Rush and X. Shi,On Orbits of Order Ideals of Minuscule Posets(2013), Journal of Algebraic Combinatorics: An International Journal, Vol. 37, Issue 3, Pages 545- 569. · Zbl 1283.06007
[16] T. Roby,Dynamical Algebraic Combinatorics and the Homomesy Phenomenon(First online: 13 April 2016); Chapter of Recent Trends in Combinatorics; Part of the IMA Volumes in Mathematics and its Applications book series (IMA, Vol. 159).
[17] J. Striker and N. Williams,Promotion and Rowmotion(2012), European Journal of Combinatorics, Vol. 33, Issue 8, Pages 1919-1942. · Zbl 1260.06004
[18] D. Grinberg, T. Roby,Iterative Properties of Birational Rowmotion I: Generalities and Skeletal Posets(2016), The Electronic Journal of Combinatorics, Vol. 23, Issue 1, Pages 1-33 · Zbl 1338.06003
This reference list is based on information provided by the publisher or from digital mathematics libraries. Its items are heuristically matched to zbMATH identifiers and may contain data conversion errors. In some cases that data have been complemented/enhanced by data from zbMATH Open. This attempts to reflect the references listed in the original paper as accurately as possible without claiming completeness or a perfect matching.