An addendum and correction to “Mathematical properties of Q-measures” (vol. 7, issue 3, pp. 737-745)

A correction is provided for the proof of a theorem announced in (Rousseau et al., 2013). We show, moreover, that in a network subdivided into three or more subgroups there is at most one node with global Q-measure equal to one. In case there are two subgroups then it is possible to have two nodes with global Q-measure equal to one. This characterization leads to a graphical representation of networks having the maximum possible number of nodes with Q-measure equal to one.