Stochastic Extinction, An Average Lyapunov Function Approach

Abstract

We study the stability of ${\mathcal{M}}_0$, an invariant subset of a Markov process $(X_t{)}_{t\ge 0}$ on a metric space $\mathcal{M}$. By building the theory of average Lyapunov functions, we formulate general criteria based on the signs of Lyapunov exponents that guarantee extinction ($X_t\to {\mathcal{M}}_0$ as $t\to \infty$). Additionally, we provide applications to a stochastic SIS epidemic model on a network with regime-switching, a stochastic differential equation version of the Lorenz system, a general class of discrete-time ecological models, and stochastic Kolmogorov systems. In many examples we improve existing results by removing unnecessary assumptions or providing sharper criteria for the extinction.

72 pages