Union and Intersection of Filtering Functions for Information Filtering

摘要

In our previous works, to establish mathematical foundation of information filtering, we defined the notion of filtering function that represents filtering as a function, and clarified the characteristics of filtering. The constructed mathematical foundation makes it possible to qualitatively evaluate various filtering methods, to optimize processing methods in filtering, or to design a declarative language for describing the filtering policy. Moreover, since current filtering methods consist of multiple methods, we have revealed the properties of composite filtering functions. However, we have not considered operations without composition. In this paper, we define filtering functions that carry out union and intersection of the filtering results, and clarify their properties. Results show that we can qualitatively represent the filtering combined by more diverse strategies and reveal their characteristics.