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.
GSP algorithm GSP algorithm ("Generalized Sequential Pattern" algorithm) is an algorithm used for sequence mining. The algorithms for solving sequence mining problems are mostly based on the "a priori" (level-wise) algorithm. One way to use the level-wise paradigm is to first discover all the frequent items in a level-wise fashion. It simply means counting the occurrences of all singleton elements in the database. Then, the transactions are filtered by removing the non-frequent items. At the end of this step, each transaction consists of only the frequent elements it originally contained. This modified database becomes an input to the GSP algorithm. This process requires one pass over the whole database.