For a dynamic system, if there is a (quasi) weakly almost periodic point but not an almost periodic point, then there exists a subsystem which is chaotic in the sense of revised Devaney.

• 摘要得到一个动力系统如果存在非几乎周期的（拟）弱几乎周期点，则存在子系统在修改的狄万内意义下是混沌的。