Research of the memory characteristics of P-set

P-set (packet sets) is a set pair which consists of interior P-set (interior packet set) and exterior P-set (exterior packet sets). By employing P-set and its structure, the concept of the ƒ -memory set of interior P-set, ƒ -memory measurement, and ƒ -variation measurement are presented in this article, further the relation theorems between the ƒ -memory and the ƒ -variation of interior P-set are proposed; similarly, the concept of the ƒ̅ -memory set of exterior P-set, the ƒ̅ -memory measurement of exterior P-set, and ƒ̅ -variation measurement are presented, moreover the relation theorem between the ƒ̅ -memory and the ƒ̅ -variation of exterior P-set is proposed. The memory characteristic is one of the important characteristics of P-set.