,
Philipp Beltran
,
Benedikt Stufler
,
Paul Thévenin
Creative Commons Attribution 4.0 International license
We first consider irreducible critical multitype Bienaymé trees and extend the results to the case, when they possess a critical irreducible component with attached subcritical components. We study these trees under two distinct conditioning frameworks: first, conditioning on the value of a linear combination of the numbers of vertices of given types; and second, conditioning on the precise number of vertices belonging to a selected subset of types. We prove that, under a finite exponential moment condition, the scaling limit as the tree size tends to infinity is given by the Brownian Continuum Random Tree. Additionally, we establish strong non-asymptotic tail bounds for the height of such trees. Our main tools include a flattening operation applied to multitype trees and sharp estimates regarding the structure of monotype trees with a given sequence of degrees.
@InProceedings{addarioberry_et_al:LIPIcs.AofA.2026.4,
author = {Addario-Berry, Louigi and Beltran, Philipp and Stufler, Benedikt and Th\'{e}venin, Paul},
title = {{Scaling Limits of Multitype Bienaym\'{e} Trees}},
booktitle = {37th International Conference on Probabilistic, Combinatorial and Asymptotic Methods for the Analysis of Algorithms (AofA 2026)},
pages = {4:1--4:16},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-435-2},
ISSN = {1868-8969},
year = {2026},
volume = {381},
editor = {Panagiotou, Konstantinos},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.AofA.2026.4},
URN = {urn:nbn:de:0030-drops-262750},
doi = {10.4230/LIPIcs.AofA.2026.4},
annote = {Keywords: branching processes, multitype trees, scaling limit}
}