Descartes snark

Last updated
Descartes snark
Descartes snark.png
Image of a Descartes snark.
Named after Blanche Descartes
Vertices 210
Edges 315
Girth 5
Chromatic index 4
Properties Cubic
Snark
Table of graphs and parameters

In the mathematical field of graph theory, a Descartes snark is an undirected graph with 210 vertices and 315 edges. It is a snark, a graph with three edges at each vertex that cannot be partitioned into three perfect matchings. It was first discovered by William Tutte in 1948 under the pseudonym Blanche Descartes. [1]

A Descartes snark is obtained from the Petersen graph by replacing each vertex with a nonagon and each edge with a particular graph closely related to the Petersen graph. Because there are multiple ways to perform this procedure, there are multiple Descartes snarks.

References

  1. Descartes, Blanche (1948), "Network-colourings", The Mathematical Gazette , 32 (299): 67–69, doi:10.2307/3610702, JSTOR   3610702, MR   0026309