Another solvable population dynamic with uniform ancestral memory

Abstract

We study a population model with non-overlapping generations, where individuals have a type and retain the memory of the types of all their ancestors. We assume that for each individual, the reproduction law depends on the empirical distribution of ancestral types, unlike for a classical multi-type branching process where it hinges on the parental type only. We further assume the mean reproduction matrix has rank one. Building on techniques from previous works with Bastien Mallein, which themselves draw on foundational contributions by Philippe Flajolet and collaborators in the context of analytic urns, we analyze the population at large generations. In particular, we determine the Malthusian parameter and estimate the expected size of the sub-population whose empirical distribution of ancestral types lies within a given set.