1.Item-Item CF algorithm
2.User-User CF algorithm
3.SVD algorithm
4.Product association algorithm
Focuses on what items are most likely to occur in conjunction with given item.
In terms of recommender system
((other_item && given_item)/given_item)
In terms of probability
prob(other_item | given_item) (expand normal Bayes rule)
5.Content-based filtering
create user profile and item-tag vector(TF-IDF)
algorithms (TF-IDF,BM-25)