How do I determine whether a graph is singly connected or not?

Question

If a graph has back edges, is it singly connected or not? By back edges I mean connections from child node to one of its ancestors, under the same root. If a node is connected to a node higher than it, but not its ancestor, then it's a cross node.

http://en.wikipedia.org/wiki/Polytree

This link clarifies the concept of singly connected graph.

Answer 1

If a graph has back edges, that doesn't prevent it from being singly-connected. But it might not be singly-connected for other reasons. For example, if the graph is undirected.