Assertion: graph's vertex | /r/HasAspect | unique parent
Facets:
value: except the root
type: OTHER
Source sentences:
text: In a rooted tree, the parent of a vertex v is the vertex connected to v on the path to the root; every vertex has a unique parent except the root which has no parent.
text: In a rooted tree, the parent of a vertex is the vertex connected to it on the path to the root; every vertex except the root has a unique parent.