Hilltop Supernatural Inflation and Gravitino Problem
  In this paper, we explore the parameter space of hilltop supernatural
inflation model and show the regime within which there is no gravitino problem
even if we consider both thermal and nonthermal production mechanisms. We make
plots for the allowed reheating temperature as a function of gravitino mass by
constraints from big-bang nucleosynthesis. We also plot the constraint when
gravitino is assumed to be stable and plays the role of dark matter.
