Endemic bubble on a simple SIS model with distributed time lag
摘要
In this paper, the complex dynamic behaviors (transcritical bifurcation at disease-free equilibrium and Hopf bifurcations at endemic equilibrium) of a SIS model with distributed time lag are exhaustively studied theoretically and numerically. The normal form coefficients of transcritical bifurcation and Hopf bifurcations are obtained by employing center manifold reduction and normal form theory, and projection method combined with Fredholm Alternative techniques, respectively. Curiously, a pair of supercritical Hopf bifurcations in opposite directions emerge near the endemic equilibrium, and a stable endemic bubble forms during the change of bifurcating parameter