A local source is a node of a directed graph with no entering edges (Borowski and Borwein 1991, p. 401; left figure), and a global source (often simply called a source) is a node in a directed graph which reaches all other nodes (Harary 1994, p. 201; right figure).

# Digraph Source

## See also

Digraph Sink, Directed Graph, Network## Explore with Wolfram|Alpha

## References

Borowski, E. J. and Borwein, J. M. (Eds.).*The HarperCollins Dictionary of Mathematics.*New York: HarperCollins, 1991.Harary, F.

*Graph Theory.*Reading, MA: Addison-Wesley, 1994.

## Cite this as:

Weisstein, Eric W. "Digraph Source." From
*MathWorld*--A Wolfram Web Resource. https://mathworld.wolfram.com/DigraphSource.html