Interior Quasinormal Modes and Strong Cosmic Censorship

Recent work has argued that the strong cosmic censorship (SCC) conjecture is violated by near-extremal Reissner-Nordstr\"om de Sitter (RNdS) black holes but respected by Kerr-de Sitter black holes. It has also been shown that the conjecture is violated by near-extremal BTZ black holes. The latter result relies on a coincidence between "exterior" and "interior" quasinormal frequencies. If this coincidence were to occur also for RNdS or Kerr-dS then it would significantly modify the conclusions of earlier work. In this paper, it is demonstrated that this coincidence does not occur for RNdS or Kerr-dS and so the conclusions of the earlier work remain valid.