 For instance, a molecule \(w\) exemplifying H2O has as parts two atoms \(h_1\) and \(h_2\) and an atom \(o\) that do not exemplify H2O; this property involves hydrogen and oxygen, which are not exemplified by \(w\); \(h_1\) and \(h_2\) exemplify hydrogen, and \(o\) exemplifies oxygen. For relational structural properties, there is the further condition that