Rank Polynomials of Fence Posets are Unimodal

Autor: Oğuz, Ezgi Kantarcı, Ravichandran, Mohan
Rok vydání: 2021
Předmět:
Druh dokumentu: Working Paper
DOI: 10.1016/j.disc.2022.113218
Popis: We prove a conjecture of Morier-Genoud and Ovsienko that says that rank polynomials of the distributive lattices of lower ideals of fence posets are unimodal. We do this by introducing a related class of circular fence posets and proving a stronger version of the conjecture due to McConville, Sagan and Smyth. We show that the rank polynomials of circular fence posets are symmetric and conjecture that unimodality holds except in some particular cases. We also apply the recent work of Elizalde, Plante, Roby and Sagan on rowmotion on fences and show many of their homomesy results hold for the circular case as well.
Comment: 21 pages, 16 figures, 2 tables
Databáze: arXiv