-#+COPYING
-(defmethod generate-directed-free-tree ((graph basic-graph) (root basic-vertex))
- (let ((new-graph (copy-top-level graph)))
- (empty! new-graph)
- (nilf (contains-undirected-edge-p new-graph))
- (neighbors-to-children new-graph root)
- (values new-graph)))
-
-;;; ---------------------------------------------------------------------------
-