which subclass of information filtering system was work of John Thomas Riedl
Recommender system A recommender system or a recommendation system (sometimes replacing "system" with a synonym such as platform or engine) is a subclass of information filtering system that seeks to predict the "rating" or "preference" that a user would give to an item.
Logic of information The logic of information, or the "logical theory of information", considers the information content of logical signs and expressions along the lines initially developed by Charles Sanders Peirce. In this line of work, the concept of information serves to integrate the aspects of signs and expressions that are separately covered, on the one hand, by the concepts of denotation and extension, and on the other hand, by the concepts of connotation and comprehension.