R. Geroch, “Limits of Spacetimes,” Communications in Mathematical Physics, Vol. 13, No. 3, 1969, pp. 180-193. doi:10.1007/BF01645486
has been cited by the following article:
TITLE: Geometric Aspects of Extremal Kerr Black Hole Entropy
AUTHORS: Ecaterina Howard
KEYWORDS: Bifurcate Killing Horizon; Extremal Kerr Black Hole; Black Hole Entropy
JOURNAL NAME: Journal of Modern Physics, Vol.4 No.3, March 21, 2013
ABSTRACT: Extreme Black Holes is an important theoretical laboratory for exploring the nature of entropy. We suggest that this unusual nature of the extremal limit could explain the entropy of extremal Kerr black holes. The time-independence of the extremal black hole, the zero surface gravity, the zero entropy and the absence of a bifurcate Killing horizon are all related properties that define and reduce to one single unique feature of the extremal Kerr spacetime. We suggest the presence of a true geometric discontinuity as the underlying cause of a vanishing entropy.