Can Strong QCD in the Early Universe Raise the Axion Decay Constant?
  We report that the hypothesis that the upper bound on the axion decay constant can be moved up beyond $10^{12}$ GeV in models with a stronger QCD in the early universe is not realized. This proof is possible by studying the superpotential in the dual model and obtaining the form of the axion potential respecting the original global symmetries. 
Jihn E. Kim (Seoul National University, Korea)