In this paper we take a closer look at snarks, a certain group of graphs that appears in graph theory. We define them as cyclically $4$-edge-connected cubic graphs of girth at least five and chromatic index four. Petersen graph is the most well-known snark, as well as the smallest and only snark on 10 vertices. The number of known snarks rises very fast with the number of vertices in a graph. Snarks can help us prove the four colour theorem as the four colour theorem is equivalent to the statement that every snark must be non-planar.
Up until 1975 only five snarks were known. In the year 1975, Rufus Isaacs classified two infinite families of snarks, depending on their construction. The first infinite family includes snarks, constructed by the dot or the star product. And the second infinite family are flower snarks, which get their name after their flower-like shape. Rufus Isaacs also produced a completely separate new snark, the double-star snark.
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