Carter  generalized the Kerr solution
by describing a rotating black hole in a four-dimensional de Sitter or anti-de Sitter background.
Valiente Kroon have developed a method based on properties of the Kerr solution
, a time-independent solution to the equations of General Relativity.
The Kerr solution, in Boyer-Lindquist coordinates and relativistic units is,
By (47) the correct expression for the Kerr solution (31) is,