A special graph vertex that is designated to turn a tree into a rooted tree or a graph into a rooted graph. The root is sometimes also called "eve," or an "endpoint" (Saaty and Kainen 1986, p. 30). Each of the graph vertices that is one graph edge further away from a given graph vertex is called a child. Nodes connected to the same node are then called siblings.

# Root Vertex

## See also

Child, Rooted Graph, Rooted Tree, Sibling, Tree, Tree Height, Vertex Depth## Explore with Wolfram|Alpha

## References

Harary, F.*Graph Theory.*Reading, MA: Addison-Wesley, p. 187, 1994.Saaty, T. L. and Kainen, P. C.

*The Four-Color Problem: Assaults and Conquest.*New York: Dover, 1986.

## Referenced on Wolfram|Alpha

Root Vertex## Cite this as:

Weisstein, Eric W. "Root Vertex." From
*MathWorld*--A Wolfram Web Resource. https://mathworld.wolfram.com/RootVertex.html