Figure 3From: Complex dynamics in an SIS epidemic model with nonlinear incidenceWhen \(R_{0}>1\). (a) \(\psi_{5}<0\), the disease-free equilibrium \(E_{0}\) is unstable and the unique positive equilibrium \(E_{5}\) is globally stable. (b) \(\psi_{5}>0\), \(E_{0}\) and \(E_{5}\) are unstable and there exists a stable limit cycleBack to article page