2 problems

Let $\sigma_0$ be a simple quasinormal mode of the Klein--Gordon equation on the near-horizon geometry with parameters $r_{\rm e}$ and $r_{\rm c}$. Let $\epsilon>0$ be small and se…

Let the initial data be sufficiently close to a Reissner–Nordström–de Sitter solution whose parameters are sufficiently close to extremal but still subextremal, and let…