Decay of correlations on towers with non-Holder continuous Jacobian and   non-exponential return time
  We establish upper bounds on the rate of decay of correlations of tower systems with summable variation of the Jacobian and integrable return time. That is, we consider situations in which the Jacobian is not Holder and the return time is only subexponentially decaying. We obtain a subexponential bound on the correlations, which is essentially the slowest of the decays of the variation of the Jacobian and of the return time. 
Jerome Buzzi, Veronique Maume-Deschamps