Abstract: P-sets(packet sets) is a pair of sets composed of internal P-set and outer P-set, wMch has dynamic character'tsties. The dynamic characteristics are got by element transfer that has random characteristics. Based on it this paper presented concepts of P(p.a)-sets,gave its structure and proved that P(p.a)-sets is the general case of P-sets,while P-sets is the special case of P(p.a)-sets. The paper discussed random and dynamic characteristics of P(p.a)-sets,and gave random relation theorems among internal P(p.a)}-set,outer P(p.a)-set and clement transfer probability,and their applications.

Key words: P-sets,P(p.a)-sets,Element transfer,Random characteristics and applications