Relating embedding and coloring properties of snarks

Bojan Mohar, Eckhard Steffen, Andrej Vodopivec


In 1969, Grünbaum conjectured that snarks do not have polyhedral embeddings into orientable surfaces. We define the defect of a graph and use it to study embeddings of superpositions of cubic graphs into orientable surfaces. Superposition was introduced by Kochol to construct snarks with arbitrary large girth. It is shown that snarks constructed by Kochol do not have polyhedral embeddings into orientable surfaces. For each k = 2 we construct infinitely many snarks with defect precisely k. We then relate the defect with the resistance r(G) of a cubic graph G which is the size of a minimum color class of a 4-edge-coloring of G. These results are then extended to deal with some weaker versions of the Grünbaum Conjecture.


Graph embedding, resistance, snark, superposition

Full Text:



ISSN: 1855-3974

Issues from Vol 6, No 1 onward are partially supported by the Slovenian Research Agency from the Call for co-financing of scientific periodical publications