Figure 1
From: Studies on the basic reproduction number in stochastic epidemic models with random perturbations
Stability modeled using the parameters \(N=1\), \(\beta = 0.5\), \(\sigma = 0.3\), \(\mu = 0.0007\), \(\eta = 0.0008\), and (a) \(\gamma = 0.6\) (upper right), (b) \(\gamma = 0.7\) (upper left), (c) \(\gamma = \beta N \frac{\eta }{\mu } - \frac{\sigma ^{2}}{2} \frac{\eta ^{2}}{\mu ^{2}} N^{2} - \mu \) (lower left) and (d) \(\gamma = 0.2\) (lower right). The initial condition is \(( N,0 ) = ( 1,0 )\) for all of them