Table 1: Some notations used in the paper.

NotationsDescription

User set,
Item set,
Items (preference of observation over user u’s one kind action)
Items (preference of observation over user u’s auxiliary action)
Items (preference of observation),
Items (absence of observation),
User index
Item index
Pair set (preference of observation over user u’s one kind action),
Pair set (preference of observation over user u’s auxiliary action),
Pair set (absence of observation),
Auxiliary coefficient, ,
The number which user u has made to item i based on one kind action
The number which user u has made to item j based on auxiliary action
Preference of user u on item i
Model parameters
User u’s latent feature vector, d is the number of latent factors
User i’s latent feature vector, d is the number of latent factors
Item i’s bias