An example input and optimal solutions to CLUSTER EDITING, SPLIT CLUSTER EDITING, and MONOPOLAR EDITING. Dashed edges are edge deletions, bold edges are edge insertions. CLUSTER EDITING and SPLIT CLUSTER EDITING produce the same two clusters but SPLIT CLUSTER EDITING assigns the blue vertex of the size-four cluster to the periphery. In an optimal solution to MONOPOLAR EDITING the two blue vertices are in the periphery which is shared between two clusters. Note that the number of necessary edge modifications decreases from CLUSTER EDITING to SPLIT CLUSTER EDITING to MONOPOLAR EDITING.