Double-star snark

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Double-star snark
Double-star snark.svg
The Double-star snark
Vertices 30
Edges 45
Radius 4
Diameter 4
Girth 6
Automorphisms 80
Chromatic number 3
Chromatic index 4
Properties Snark

In the mathematical field of graph theory, the double-star snark is a snark with 30 vertices and 45 edges.[1]

In 1975, Rufus Isaacs introduced two infinite families of snarks—the flower snark and the BDS snark, a family that includes the two Blanuša snarks, the Descartes snark and the Szekeres snark (BDS stands for Blanuša Descartes Szekeres).[2] Isaacs also discovered one 30-vertex snark that does not belongs to the BDS family and that is not a flower snark — the double-star snark.

As a snark, the double-star graph is a connected, bridgeless cubic graph with chromatic index equal to 4. The double-star snark is non-planar and non-hamiltonian but is hypohamiltonian.[3]



  1. ^ Weisstein, Eric W., "Double Star Snark", MathWorld.
  2. ^ Isaacs, R. (1975), "Infinite families of non-trivial trivalent graphs which are not Tait-colorable", American Mathematical Monthly (Mathematical Association of America) 82 (3): 221–239, doi:10.2307/2319844, JSTOR 2319844 
  3. ^ Weisstein, Eric W., "Hypohamiltonian Graph", MathWorld.