Quasi-stationary distribution for continuous-state branching processes with competition

TL;DR

This paper investigates the existence and uniqueness of quasi-stationary distributions for continuous-state branching processes with competition, demonstrating that strong competition ensures convergence to a unique distribution.

Contribution

It establishes conditions under which a unique quasi-stationary distribution exists for these processes, extending previous work by analyzing their properties and convergence behavior.

Findings

Existence of a unique quasi-stationary distribution under strong competition

Proved strong Feller, trajectory Feller, Lyapunov, weak Feller properties, and irreducibility

All initial distributions are attracted exponentially fast to the quasi-stationary distribution

Abstract

We study quasi-stationary distribution of the continuous-state branching process with competition introduced in Berestycki, Fittipaldi and Fontbona\ (Probab. Theory Relat. Fields, 2018). This process is constructed as the unique strong solution to a stochastic integral equation with jumps. An important example is the logistic branching process constructed in Lambert (Ann. Appl. Probab., 2005). We establish the strong Feller property,trajectory Feller property, Lyapunov condition, weak Feller property and irreducibility, respectively. These properties together allow us to prove that when the competition term is strong enough near $+\infty$, then there is a unique quasi-stationary distribution, which attracts all initial distributions with exponential rates.