Topological graph theory
Journal of Combinatorial Theory Series B
Superposition and constructions of graphs without nowhere-zero k-flows
European Journal of Combinatorics
Families of Dot-Product Snarks on Orientable Surfaces of Low Genus
Graphs and Combinatorics
Hi-index | 0.00 |
The Four Color Theorem is equivalent with its dual form stating that each 2-edge-connected 3-regular planar graph is 3-edge-colorable. In 1968, Grünbaum conjectured that similar property holds true for any orientable surface, namely that each 3-regular graph with a polyhedral embedding in an orientable surface has a 3-edge-coloring. Note that an embedding of a graph in a surface is called polyhedral if its geometric dual has no multiple edges and loops. We present a negative solution of this conjecture, showing that for each orientable surface of genus at least 5, there exists a 3-regular non 3-edge-colorable graph with a polyhedral embedding in the surface.