is_tree¶
- is_tree(G)[source]¶
Returns True if G is a tree.
A tree is a connected graph with no undirected cycles.
For directed graphs, G is a tree if the underlying graph is a tree. The underlying graph is obtained by treating each directed edge as a single undirected edge in a multigraph.
Parameters: G (graph) – The graph to test. Returns: b – A boolean that is True if G is a tree. Return type: bool Notes
In another convention, a directed tree is known as a polytree and then tree corresponds to an arborescence.
See also