Abstract
We introduce a Poissonization method to study the coalescent structure of uniform samples from branching processes. This method relies on the simple observation that a uniform sample of size k taken from a random set with positive Lebesgue measure may be represented as a mixture of Poisson samples with rate λ and mixing measure . We develop a multitype analogue of this mixture representation, and use it to characterise the coalescent structure of multitype continuous-state branching processes in terms of random multitype forests. Thereafter we study the small time asymptotics of these random forests, establishing a correspondence between multitype continuous-state branching processes and multitype Λ-coalescents.
Funding Statement
The first author was supported in the early stages by the ERC grant Integrable Random Structures and in the later stages by the FWF grant Asymptotic Geometric Analysis and Applications.
Citation
Samuel G. G. Johnston. Amaury Lambert. "The coalescent structure of uniform and Poisson samples from multitype branching processes." Ann. Appl. Probab. 33 (6A) 4820 - 4857, December 2023. https://doi.org/10.1214/23-AAP1934
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