Two - Way Rule Acquisition Based On Class Background

Formal concept analysis theory was put forward in 1982 by the German mathematician Wille R. It provides us a method of data analysis. As the basis of artificial intelligence, formal concept analysis has attracted more and more attention and been applied in many fields such as automaticcontrol, knowledge discovery, medical diagnosis, and pattern recognition.Rule acquisition is a hot issue of knowledge discovery and the studies of it mainly focus on how to get decisions from conditions. However, the opposite direction of this process may be more meaningful in our real life. For example, we need to explore the causes or the nature of things from the results.Based on this, the paper studies the following questions:1. Based on the definition of extension subset family,the relationship between extent of the original concept lattice and the class concept lattice is obtained, namely, giving the relationship between these two kinds of concepts from the perspective of power set.2. In a weak consistent formal decision context, the rule set of this context and the rule set of the corresponding class context are compared from the number and the redundancy of the rules.3.The reverse rules with specific meaning are proposed and how to obtain these reverse rules via class concept lattice of condition contextare studied. Finally, based on the relationship between extent of the original concept lattice and the class concept lattices, acquisition method of two-way rule is given.