,
Hsien-Kuei Hwang
,
Noah A. Rosenberg
Creative Commons Attribution 4.0 International license
The Colijn-Plazzotta ranking is a certain bijection between the unlabeled binary rooted trees and the positive integers, such that the integer associated with a tree is determined from the integers associated with the two immediate subtrees of its root. Letting a_n denote the minimal Colijn-Plazzotta rank among all trees with a specified number of leaves n, the sequence {a_n} begins 1, 2, 3, 4, 6, 7, 10, 11, 20, 22, 28, 29, 53, 56, 66, 67 (OEIS A354970). Here we show that a_n ∼ 2 [2^{P(log₂ n)}]ⁿ, where P varies as a periodic function dependent on {log₂ n} and satisfies 1.24602 < 2^{P(log₂ n)} < 1.33429.
@InProceedings{doboli_et_al:LIPIcs.AofA.2024.18,
author = {Doboli, Michael R. and Hwang, Hsien-Kuei and Rosenberg, Noah A.},
title = {{Periodic Behavior of the Minimal Colijn-Plazzotta Rank for Trees with a Fixed Number of Leaves}},
booktitle = {35th International Conference on Probabilistic, Combinatorial and Asymptotic Methods for the Analysis of Algorithms (AofA 2024)},
pages = {18:1--18:14},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-329-4},
ISSN = {1868-8969},
year = {2024},
volume = {302},
editor = {Mailler, C\'{e}cile and Wild, Sebastian},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.AofA.2024.18},
URN = {urn:nbn:de:0030-drops-204530},
doi = {10.4230/LIPIcs.AofA.2024.18},
annote = {Keywords: Colijn-Plazzotta ranking, recurrences, unlabeled trees}
}