On Coloring Problems of Snark Families

Snarks are cubic bridgeless graphs of chromatic index 4 which had their origin in the search of counterexamples to the Four Color Theorem. In 2003, Cavicchioli et al. proved that for snarks with less than 30 vertices, the total chromatic number is 4, and proposed the problem of finding (if any) the smallest snark which is not 4-total colorable. Since then, only two families of snarks have had their total chromatic number determined to be 4, namely the Flower Snark family and the Goldberg family. ve that the total chromatic number of the Loupekhine family is 4. We study the dot product, a known operation to construct snarks. We consider families of snarks using the dot product, particularly subfamilies of the Blanusa families, and obtain a 4-total coloring for each family. We study edge coloring properties of girth trivial snarks that cannot be extended to total coloring. We classify the snark recognition problem as CoNP-complete and establish that the chromatic number of a snark is 3.