User-Item graphs
Neighborhood definition
Random Walks
Personalized PageRank or the SimRank method to determine the k most similar users.
Katz Measure
Katz(i,j)=t=1βββΞ²tβ
Ξ·ij(t)β Ξ·ij(t)β is the number of walks of length t between nodes i and j. The value of Ξ² is a discount factor.
K=i=1βββ(Ξ²A)i=(IβΞ²A)β1βI User-User Graphs
Item-Item Graphs