ABSTRACT
Quantum Electrodynamics is built around the Abelian group. Its counterpart for strong interactions is Quantum Chromodynamics built around the non-Abelian group. One can actually build an antisymmetric wave function within the three degrees of freedom available, but it fails to reproduce the physical observables of baryons. Only the symmetric quark model wave function works. The idea was to have colour produce a fully antisymmetric component of the wave function, so that when multiplied with the symmetric quark model wave function, the total wave function would be antisymmetric. The three-valued colour is an experimentally confirmed quantum number. And hence colour, which was initially an ad hoc concept, later turned out to be an empirically confirmed reality of hadrons. So for three quark-colour combinations, states are obtained by counting the number of symmetric and antisymmetric pair exchanges involved in a particular representation.
