We interpret the number of good four-colourings of the faces of a trivalent,
spherical polyhedron as the 2-holonomy of the 2-connection of a fibered
category, phi, modeled on Rep(sl(2)) and defined over the dual triangulation,
T. We also build an sl(2)-bundle with connection over T, that is a global,
equivariant section of phi, and we prove that the four-colour theorem is
equivalent to the fact that the connection of this sl(2)-bundle vanishes
nowhere. This interpretation may be a first step toward a cohomological proof
of the four-colour theorem.