Global stability of an SEI epidemic model with general contact rate

This paper consider an SEI epidemic model with general contact rate that incorporates constant recruitment and have infectious force in the latent period and infected period. By means of Lyapunov function and LaSalle's invariant set theorem, we proved the global asymptotical stable results of the disease-free equilibrium and the epidemic equilibrium by using the Poincarè-Bendixson property.