Table 2.

Link prediction score function for topology-based node neighborhood metrics in bipartite graphs.

Score metric	Score formula
CN	$|\mathrm{\Gamma }\left(x\right){\cap }^{}{\mathrm{\Gamma }}^{\prime }\left(y\right)$
JC	$\frac{\left|\mathrm{\Gamma }\left(x\right){\cap }^{}{\mathrm{\Gamma }}^{\prime }\left(y\right)\right|}{\left|\mathrm{\Gamma }\left(x\right){\cup }^{}{\mathrm{\Gamma }}^{\prime }\left(y\right)\right|}$
PA	$\left|\mathrm{\Gamma }\left(x\right)\right|\times \left|\mathrm{\Gamma }\left(y\right)\right|$
AA	$\sum _{z\in \mathrm{\Gamma }(x){\cap }^{}{\mathrm{\Gamma }}^{\prime }(y)}\frac{1}{\log \left|\mathrm{\Gamma }\left(z\right)\right|}$

Abbreviations: AA, Adamic and Adar; CN, common neighbors; JC, Jaccard; PA, preferential attachment.