Definitions for "Undirected graph"
Keywords:  graph, iff, unordered, edge, vertices
(n.)a graph whose edges have no orientation.
a set of nodes (or vertices ) together with a set of pairs of those vertices, called arcs or edges
a unit disk graph iff its vertices can be put in one to one correspondence with equal sized circles in a plane in such a way that two vertices are joined by an edge iff the corresponding circles intersect