The Loupekine snarks are the two snarks on 22 vertices and 33 edges illustrated above. They are implemented in the Wolfram
Language as GraphData["LoupekineSnark1"]
and GraphData["LoupekineSnark2"],
respectively.
The Loupekine snarks were found independently in the embeddings shown above by Collier and Schmeichel (1978) who erroneously characterized them as "two new cubic hypohamiltonian graphs."
Collier, J. B. and Schmeichel, E. F. "Systematic Searches for Hypohamiltonian Graphs." Networks8, 193-200, 1978.Holton,
D. A. and Sheehan, J. The
Petersen Graph. Cambridge, England: Cambridge University Press, pp. 82
and 100-102, 1993.Read, R. C. and Wilson, R. J. An
Atlas of Graphs. Oxford, England: Oxford University Press, p. 279, 1998.
