Robertson–Wegner graph

From HandWiki
Short description: 5-regular undirected graph with 30 vertices and 75 edges
Robertson–Wegner graph
Named afterNeil Robertson
Vertices30
Edges75
Radius3
Diameter3
Girth5
Automorphisms20
Chromatic number4
Chromatic index5[1]
PropertiesCage
Table of graphs and parameters

In the mathematical field of graph theory, the Robertson–Wegner graph is a 5-regular undirected graph with 30 vertices and 75 edges named after Neil Robertson and Gerd Wegner.[2][3][4]

It is one of the four (5,5)-cage graphs, the others being the Foster cage, the Meringer graph, and the Wong graph.

It has chromatic number 4, diameter 3, and is 5-vertex-connected.

Algebraic properties

The characteristic polynomial of the Robertson–Wegner graph is

(x5)(x2)8(x+1)(x+3)4(x4+2x34x25x+5)2(x4+2x36x27x+11)2.

References

  1. Weisstein, Eric W.. "Class 2 Graph". http://mathworld.wolfram.com/Class2Graph.html. 
  2. Weisstein, Eric W.. "Robertson–Wegner Graph". http://mathworld.wolfram.com/Robertson-WegnerGraph.html. 
  3. Bondy, J. A. and Murty, U. S. R. Graph Theory with Applications. New York: North Holland, p. 238, 1976.
  4. Wong, P. K. "A note on a paper of G. Wegner", Journal of Combinatorial Theory, Series B, 22:3, June 1977, pgs 302-303, doi:10.1016/0095-8956(77)90081-8