2.3.2 Loyalty and node-loyalty of the network
We measured the proportion of preserved edges (\(\theta)\) of a given
premises between two consecutive years, \(t-1\) and\(\ t\), for the
entire network. In order to quantify\(\ \theta_{i}^{t-1,\ t}\), we
define \(Y_{i}^{t-1}\)as the set of edges from a premises \(i\) in the
time \(t-1\) and \({\ Y}_{i}^{t}\) as the set of edges from a premises\(i\) at time \(t\). Then, \(\theta_{i}^{t-1,\ t}\)is given by the
Jaccard Index in equation 2 (VALDANO et al., 2015; SCHULZ et al., 2017).