Diameter of a graph
where denotes the distance between two vertices. In words, the diameter of a graph is the maximum, over all vertices, of the eccentricity of that vertex.
Note that for a connected finite graph, the diameter is finite. For an infinite connected graph, the diameter may be finite or . A graph of finite diameter is a connected graph (finite or infinite) whose diameter is finite.
For a graph that is not connected, we can consider the diameter to be either or undefined.
|Invariant||Meaning||Relation with radius|
|Radius of a graph||minimum of eccentricities of vertices||Radius Diameter Twice the radius|