Remark
(i) From conditions (13)–(16) it may be noted that (K + d) and d have stabilizing effects on the system while K alone has destabilizing effect.
(ii) Since the equilibrium number of infected nodes decreases as the growth of antivirus software increases in presence of a protected class, these theorems imply that under certain condition, the infected computer network can be cleaned with the antivirus software efficiently when a separate class of protected nodes is formed.