A snark on 30 vertices with edge chromatic number 4. It is implemented in the Wolfram Language as GraphData["DoubleStarSnark"].
The double star snark is a platypus graph.
Double Star Snark
See also
SnarkPortions of this entry contributed by Ed Pegg, Jr. (author's link)
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References
Holton, D. A. and Sheehan, J. The Petersen Graph. Cambridge, England: Cambridge University Press, pp. 98-100, 1993.Isaacs, R. "Infinite Families of Nontrivial Trivalent Graphs Which Are Not Tait Colorable." Amer. Math. Monthly 82, 221-239, 1975.Referenced on Wolfram|Alpha
Double Star SnarkCite this as:
Pegg, Ed Jr. and Weisstein, Eric W. "Double Star Snark." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/DoubleStarSnark.html