Figure 1

Illustration of incomplete hierarchical labels for proteins annotated with MIPS FunCat labels. A rectangle represents a protein (pi, i∈{1,2,3}); an ellipse denotes a function label, and a undirected line between rectangles captures a protein-protein interaction (the more reliable the interaction is, the thicker the line is). All the functional labels (including the missing function labels denoted by color ellipses with question marks ‘?’) in the ellipses should be associated with the proteins, but only the functional labels in the white ellipses are known. For better visualization, other functional labels (i.e., ‘12.03’ and ‘03’, which are not ground-truth labels for these proteins), are not plotted in the Figure.