Editing Tree (graph theory) (section)

===Polyforest===
A {{em|polyforest}} (or directed forest or oriented forest) is a directed acyclic graph whose underlying undirected graph is a forest. In other words, if we replace its directed edges with undirected edges, we obtain an undirected graph that is acyclic.

As with directed trees, some authors restrict the phrase "directed forest" to the case where the edges of each connected component are all directed towards a particular vertex, or all directed away from a particular vertex (see [[Arborescence (graph theory)|branching]]).<ref name=kozlov/>