Projectively nonsingular horizons in Kerr-NUT–de Sitter spacetimes
Projectively nonsingular horizons in Kerr-NUT–de Sitter spacetimes
It was recently discovered that Killing horizons in the generic Kerr-NUT--(anti-) de Sitter spacetimes are projectively singular, i.e., their spaces of the null generators have singular geometry. Only if the cosmological constant takes the special value determined by the Kerr and NUT parameters, and the radius of the horizon, then …