Watkins snark

In the mathematical field of graph theory, the Watkins snark is a snark with 50 vertices and 75 edges. It was discovered by John J. Watkins in 1989.

Watkins snark
The Watkins snark
Named after	J. J. Watkins
Vertices	50
Edges	75
Radius	7
Diameter	7
Girth	5
Automorphisms	5
Chromatic number	3
Chromatic index	4
Book thickness	3
Queue number	2
Properties	Snark
Table of graphs and parameters

As a snark, the Watkins graph is a connected, bridgeless cubic graph with chromatic index equal to 4. The Watkins snark is also non-planar and non-hamiltonian. It has book thickness 3 and queue number 2.

Another well known snark on 50 vertices is the Szekeres snark, the fifth known snark, discovered by George Szekeres in 1973.

Gallery

• 
  The chromatic number of the Watkins snark is 3.
• 
  The chromatic index of the Watkins snark is 4.

Edges

[[1,2], [1,4], [1,15], [2,3], [2,8], [3,6], [3,37], [4,6], [4,7], [5,10], [5,11], [5,22], [6,9], [7,8], [7,12], [8,9], [9,14], [10,13], [10,17], [11,16], [11,18], [12,14], [12,33], [13,15], [13,16], [14,20], [15,21], [16,19], [17,18], [17,19], [18,30], [19,21], [20,24], [20,26], [21,50], [22,23], [22,27], [23,24], [23,25], [24,29], [25,26], [25,28], [26,31], [27,28], [27,48], [28,29], [29,31], [30,32], [30,36], [31,36], [32,34], [32,35], [33,34], [33,40], [34,41], [35,38], [35,40], [36,38], [37,39], [37,42], [38,41], [39,44], [39,46], [40,46], [41,46], [42,43], [42,45], [43,44], [43,49], [44,47], [45,47], [45,48], [47,50], [48,49], [49,50]]