The Difference between Abelian and Non-Abelian Models: Fact and Fancy
The commonly accepted belief that non-Abelian and Abelian models are different because of the presence/absence of instantons and/or perturbative asymptotic freedom is analyzed from a historical perspective. The presentation covers the major developments which brought about this dogma, as well as all the supportive evidence produced since. For a model possessing both asymptotic freedom and instantons it is shown rigorously that a disorder variable varies nonanalytically with the temperature.