Singularity theorems for the Reissner-Nordstrom spacetime and topology change in regular black holes

In this work we show several singularity theorems which can be applied to the Reissner-Nordstrom spacetime. To date, only two results [Phys. Rev. D 50, 3692 (1994); Lett. Math. Phys. 110, 2383 (2020)] have predicted null incompleteness in this case. In addition, we show that regular black holes in the Bardeen category have noncompact slices without the standard assumption regarding the knowledge of regions at infinity and, therefore, that they exhibit topology changes.