Given two vertices (contexts) c i and c j , let N (c i , c j ) be the set of their neighbours and K(c i , c j ) be the set of edges between the vertices in N (c i , c j ).
the maximum number of edges that could exist between vertices in the similarity of c i , c j is set equal to the number of edges that actually exist in that neighbourhood divided by the total number of edges that could exist ( ).