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Julio Ernesto Nava Trejo

Publications and source records attributed to Julio Ernesto Nava Trejo.

2 recordsLinked to original sources

$Λ$-Seed-Bank-Wright-Fisher process conditioned on fixation

We investigate the $Λ$-Seed-Bank-Wright-Fisher process, a model describing allele frequency dynamics in populations exhibiting both skewed offspring distributions and dormancy. By performing a change of measure, we condition this process on the eventual fixation of a specified genetic type. The resulting process is again a $Λ$-Wright-Fisher process with a seed bank, but now features coordinated mutations driven by a random switching environment. Our analysis relies on two key techniques: the lookdown construction and sampling duality. These tools provide a pathwise construction of the conditioned process while preserving a means to recover the conditioned population genealogy. The resulting genealogy corresponds to a structured $Λ$-coalescent with coordinated mutations determined by the switching environment.

math.PR↗

Genealogies under logistic growth

We derive the asymptotic behaviour of the genealogy of a logistic branching process in the setting where the equilibrium population size is large. In three regimes on the tail of the offspring distribution we recover the Kingman, $\text{Beta}(2-α, α)$ and Bolthausen-Sznitman coalescents as a scaling parameter governing the population size is taken to infinity, the deduction going via the convergence in distribution of a modified lookdown construction. This resolves a question asked in arxiv:2501.16837 who studied the same population process forwards in time and showed convergence of the type frequency process to the corresponding $Λ$-Fleming-Viot process in each regime.

math.PR↗