Undirected Graph
An UndirectedGraph is a DataStructure containing a vertex set V and an edge set E, where each edge is an unordered pair of vertices.
Variants of this data structure:
- Ordered pairs may be used to hold the vertices instead of unordered pairs, resulting in a DirectedGraph.
- Weights may be associated with the edges, resulting in a WeightedUndirectedGraph.
Definition: http://www.nist.gov/dads/HTML/undirectgraf.html