Abstract: Function P-sets are a set pair which are composed of function internal packetsets S^F and function outer packet sets S^F or (S^F, S^F) are function P-sets. Function P-sets have dynamic characteristics and law characteristics. Based on function P-sets, P-information law discovery theorems which has attribute supplementing-deleting are given. Mining-discovery and mining-discovery theorems of unknown information law are proposed. Function P-sets are a new theory and new method to research dynamic information laws for information systems. 

Key words: function P-sets, dynamic characteristics, law characteristics, law sptitsynthesis, law discovery