Fig. 3

Example for a digraph (A) where Alg. 1 does not lead to an optimal BMG editing. The set \({\mathcal {R}}(\vec {G},\sigma )\) is empty and thus consistent. B The tree \(T={{\,\mathrm{Aho}\,}}({\mathcal {R}}(\vec {G},\sigma ), V(\vec {G}))\) and (C) its corresponding BMG. The two arcs (b, a) and \((b,a')\) have been inserted. D A tree \((T',\sigma )\) and (E) its corresponding BMG \(\vec {G}(T',\sigma )\) in which only the arc (b, a) has been inserted