Correction to "Vertex Entropy as a Critical Node Measure in Network Monitoring"

From Definition 2 in the above-named work, we have for a simple graph G=(V,E) , the following expression for the chromatic entropy I_{C}(G) of a graph: \begin{equation*} I_{C}\left ({G}\right) = \min _{\left \{{C_{i}}\right \}} - \sum _{i=1}^{N_{c}} \frac {|C_{i}|}{n} \log _{2} \frac {|C_{i}|}{n} \tag{1}\end{equation*}