Double-star snark

{{infobox graph

| name = Double-star snark

| image = 220px

| image_caption = The Double-star snark

| namesake =

| vertices = 30

| edges = 45

| diameter = 4

| radius = 4

| girth = 6

| automorphisms = 80

| chromatic_number = 3

| chromatic_index = 4

| properties = Snark
Hypohamiltonian

|book thickness=3|queue number=2}}

In the mathematical field of graph theory, the double-star snark is a snark with 30 vertices and 45 edges.{{MathWorld|title=Double Star Snark|urlname=DoubleStarSnark}}

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).{{Citation | first=R.|last= Isaacs| title=Infinite families of non-trivial trivalent graphs which are not Tait-colorable| journal=American Mathematical Monthly| volume=82| year=1975| pages=221–239| doi=10.2307/2319844 | issue=3 | publisher=Mathematical Association of America | jstor=2319844}} Isaacs also discovered one 30-vertex snark that does not belong 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.{{MathWorld|title=Hypohamiltonian Graph|urlname=HypohamiltonianGraph}} It has book thickness 3 and queue number 2.Wolz, Jessica; Engineering Linear Layouts with SAT. Master Thesis, University of Tübingen, 2018