,
Michael Fuchs
,
Bernhard Gittenberger
,
Noah A. Rosenberg
Creative Commons Attribution 4.0 International license
Galled trees appear in problems concerning admixture, horizontal gene transfer, hybridization, and recombination. Building on a recursive enumerative construction, we study the asymptotic behavior of the number of rooted binary unlabeled (normal) galled trees as the number of leaves n increases, maintaining a fixed number of galls g. We find that the exponential growth with n of the number of rooted binary unlabeled normal galled trees with g galls has the same value irrespective of the value of g ≥ 0. The subexponential growth, however, depends on g; it follows c_g n^{2g-3/2}, where c_g is a constant dependent on g. Although for each g, the exponential growth is approximately 2.4833ⁿ, summing across all g, the exponential growth is instead approximated by the much larger 4.8230ⁿ.
@InProceedings{agranattamir_et_al:LIPIcs.AofA.2024.27,
author = {Agranat-Tamir, Lily and Fuchs, Michael and Gittenberger, Bernhard and Rosenberg, Noah A.},
title = {{Asymptotic Enumeration of Rooted Binary Unlabeled Galled Trees with a Fixed Number of Galls}},
booktitle = {35th International Conference on Probabilistic, Combinatorial and Asymptotic Methods for the Analysis of Algorithms (AofA 2024)},
pages = {27:1--27:14},
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.2024.27},
URN = {urn:nbn:de:0030-drops-204626},
doi = {10.4230/LIPIcs.AofA.2024.27},
annote = {Keywords: galled trees, generating functions, phylogenetics, unlabeled trees}
}