An orientation of an undirected graph 
is an assignment of exactly one
direction to each of the edges of 
. Only connected, bridgeless graphs can have a strong orientation
(Robbins 1939; Skiena 1990, p. 174). An oriented complete
graph is called a tournament.
Graph Orientation
See also
Directed Graph, TournamentExplore with Wolfram|Alpha
References
Robbins, H. E. "A Theorem on Graphs with an Application to a Problem of Traffic Control." Amer. Math. Monthly 46, 281-283, 1939.Skiena, S. Implementing Discrete Mathematics: Combinatorics and Graph Theory with Mathematica. Reading, MA: Addison-Wesley, 1990.Referenced on Wolfram|Alpha
Graph OrientationCite this as:
Weisstein, Eric W. "Graph Orientation." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/GraphOrientation.html