English

Cyclic sieving phenomena for trees and tree-rooted maps

Combinatorics 2025-12-23 v1

Abstract

We prove cyclic sieving phenomena satisfied by corner-rooted plane trees (alias ordered trees). The sets of rooted plane trees that we consider are: (1) all trees with nn nodes; (2) all trees with nn nodes and kk leaves; (3) all trees with a given degree distribution of the nodes. Moreover, we consider four different cyclic group actions: (1) the root is moved to the next corner along a tour of the tree; (2) only trees in which the root is at a leaf are considered, and the action moves the root to the next leaf; (3) only trees in which the root is at a non-leaf are considered, and the action moves the root to the next non-leaf corner; (4) only trees in which the root is at a node of degree δ\delta are considered, for a fixed δ\delta, and the action moves the root to the next corner of this type. We prove a cyclic sieving phenomenon for each meaningful combination of these sets and actions. As a bonus, we also establish corresponding cyclic sieving phenomena for tree-rooted planar maps.

Keywords

Cite

@article{arxiv.2512.18656,
  title  = {Cyclic sieving phenomena for trees and tree-rooted maps},
  author = {Mireille Bousquet-Mélou and Christian Krattenthaler},
  journal= {arXiv preprint arXiv:2512.18656},
  year   = {2025}
}

Comments

52 pages, 13 figures

R2 v1 2026-07-01T08:35:24.732Z