Questionable Arguments for the Correctness of Perturbation Theory in Non-Abelian Models
We analyze the arguments put forward recently by Niedermayer et al in favor of the correctness of conventional perturbation theory in non-Abelian models and supposedly showing that our super-instanton counterexample was sick. We point out that within their own set of assumptions, the proof of Niedermayer et al regarding the correctness of perturbation theory is incorrect and provide a correct proof under more restrictive assumptions. We reply also to their claim that the S-matrix bootstrap approach of Balog et al supports the existence of asymptotic freedom in the O(3) model.