The holographic dark energy in a non-flat universe

We study the model for holographic dark energy in a spatially closed universe, generalizing the proposal in hep-th/0403127 for a flat universe. We provide independent arguments for the choice of the parameter c = 1 in the holographic dark energy model. On the one hand, c cannot be less than 1, to avoid violating the second law of thermodynamics. On the other hand, observation suggests c to be very close to 1; it is hard to justify a small deviation of c from 1 if c>1.