Table 1.

Similarity metrics and their formulaic definitions

Similarity index	Definition/Formula
Jaccard coefficient45	$\frac{\left|\Gamma \left(d\right)\cap \Gamma \left(a\right)\right|}{\left|\Gamma \left(d\right)\cup \Gamma \left(a\right)\right|}$
Dice index46	$\frac{2\times \left|\Gamma \left(d\right)\cap \Gamma \left(a\right)\right|}{D_d+D_a}$
Adamic/Adar index47	${\sum }_{zϵ\Gamma \left(d\right)\cap \Gamma \left(a\right)\mathrm{}}\frac{1}{\log \left|\Gamma \left(z\right)\right|}$
Simpson index48	$\frac{\left|\Gamma \left(d\right)\cap \Gamma \left(a\right)\right|}{Min(D_d,D_a)}$
Geometric index49	$\frac{{\left|\Gamma \left(d\right)\cap \Gamma \left(a\right)\right|}^2}{D_d\times D_a}$