Gedanken zur Vier-Farben-Vermutung
- Cite this article as:
- Fleischner, H. Monatshefte für Mathematik (1975) 79: 201. doi:10.1007/BF01304073
Some thoughts on the four colour conjecture
It is shown that the four colour conjecture is equivalent to a conjecture on the existence of spanning Eulerian subgraphs of a certain type in triangulations of the plane. From this, a simple proof of Heawood's Equivalence Theorem is given. Moreover, an elementary operation is defined for triangulations of the plane; and by repeated application of this operation one can construct a given colouring from another given colouring.