Dipole graph

Dipole graph
Vertices	2
Edges	n
Diameter	1
Chromatic number	2
Chromatic index	n

In graph theory, a dipole graph (also called a dipole or bond graph) is a multigraph consisting of two vertices connected with a number of parallel edges. A dipole graph containing n edges is called the order-n dipole graph, and is denoted by D_n. The order-n dipole graph is dual to the cycle graph C_n.

The honeycomb as an abstract graph is the maximal abelian covering graph of the dipole graph D₃, while the diamond crystal as an abstract graph is the maximal abelian covering graph of D₄.

References

• Weisstein, Eric W. "Dipole Graph". MathWorld. 

• Jonathan L. Gross and Jay Yellen, 2006. Graph Theory and Its Applications, 2nd Ed., p. 17. Chapman & Hall/CRC. ISBN 1-58488-505-X
• Sunada T., Topological Crystallography, With a View Towards Discrete Geometric Analysis, Springer, 2013, ISBN 978-4-431-54176-9 (Print) 978-4-431-54177-6 (Online)