On a class of critical Markov branching processes with non-homogeneous Poisson immigration
Kosto V. Mitov, Nikolay M. Yanev
TL;DR
The paper analyzes a class of critical Markov branching processes with infinite offspring variance and non-homogeneous Poisson immigration. By leveraging functional equations for generating functions and regular variation tools, it derives the asymptotics of the non-visitation probability $P\{Y(t)>0\}$ and identifies four distinct limit-distribution regimes under different normalizations, ranging from stable laws to a Uniform$(0,1)$ limit. The results hinge on the tail indices $\alpha$ (immigration) and $\gamma$ (offspring) and the slowly varying components, linking the immigration tail to the limit laws and revealing how heavy-tailed immigration shapes long-time behavior. These findings advance understanding of critical branching dynamics with time-inhomogeneous immigration and infinite-variance offspring, with potential applications to biological population dynamics and cellular systems where immigration occurs in a nonstationary manner.
Abstract
The paper studies a class of critical Markov branching processes with infinite variance of the offspring distribution. The processes admit also an immigration component at the jump-points of a non-homogeneous Poisson process, assuming that the mean number of immigrants is infinite and the intensity of the Poisson process converges to a constant. The asymptotic behavior of the probability for non-visiting zero is obtained. Proper limit distributions are proved, under suitable normalization of the sample paths, depending on the offspring distribution and the distribution of the immigrants.
