I have a graph that contains all the word of a text. This graph is a a
directed acyclic graph.
I want to reconstruct sequences of this text so I need to get all the nodes
and edges that are dependent of a root node or their children. In other
words I want a Sub-tree of a tree.
I cant get it with a recursive ad-hoc function, using out_neighbours(), but
I am wondering if there is another more efficient way to obtain it. I
searched in the doc but i don't find it.