Fig. 2

a Böcker and coworkers' fragmentation graph. Each vertex corresponds to a candidate formula for some mass in the mass spectrum, and vertices of the same color are candidate formulae of the same mass. Observe that there is no line between the \(\hbox {C}_{7}\hbox {H}_{6}\hbox {O}\) and \(\hbox {C}_{8}\hbox {H}_{5}\hbox {O}_{3}\) vertices, as they are not subformulae of each other. b A possible subformula graph, which is a subgraph of a and also explains the same mass spectrum encoded by (a). Note that all vertices possess distinct colours, which means masses in the spectrum are only assigned a maximum of one candidate formula. c A possible fragmentation tree (colourful subtree) of Böcker and coworkers. The vertices are also distinct colours, but each vertex only has one incoming edge