For example, to reflect this, ??i can be defined as v/N, where v is the number genres-present as alternatives when a selection is made, and N is the total number of genres available (for example, during the viewing selection, only 3 types of movies are available, while in total there can be 12 genres, then the weighting function ??i is 3/12=0.25; if on the other hand, 10 out of 12 genres were pres