Comment on "Quantum and Classical Glass Transitions in   LiHo$_{x}$Y$_{1-x}$F$_4$" by C. Ancona-Torres, D.M. Silevitch, G. Aeppli, and   T. F. Rosenbaum, Phys. Rev. Lett. 101, 057201 (2008)
  We show in this comment that the claim by Ancona-Torres et al. of an equilibrium quantum or classical phase transition in the LiHo$_x$Y$_{1-x}$F$_4$ system is not supported by a rigorous scaling analysis. 
P. E. J\"onsson, R. Mathieu, W. Wernsdorfer, A. M. Tkachuk, B. Barbara