Title:	K-causality and degenerate spacetimes
Authors:	Dowker, H.F. Garcia, R.S. Surya, Sumati
Issue Date:	Nov-2000
Publisher:	Institute of Physics
Citation:	Classical and Quantum Gravity, 2000, Vol.17, Issue 21, p 4377-4396
Abstract:	The causal relation K+ was introduced by Sorkin and Woolgar to extend the standard causal analysis of C2 spacetimes to those that are only C0. Most of their results also hold true in the case of metrics with degeneracies which are C0 but vanish at isolated points. In this paper we seek to examine K+ explicitly in the case of topology-changing `Morse histories' which contain degeneracies. We first demonstrate some interesting features of this relation in globally Lorentzian spacetimes. In particular, we show that K+ is robust and the Hawking and Sachs characterization of causal continuity translates into a natural condition in terms of K+. We then examine K+ in topology-changing Morse spacetimes with the degenerate points excised and then for the Morse histories in which the degenerate points are reinstated. We find further characterizations of causal continuity in these cases.
Description:	Restricted Access. An open-access version is available at arXiv.org (one of the alternative locations)
URI:	http://hdl.handle.net/2289/4551
ISSN:	0264-9381 1361-6382 (online)
Alternative Location:	http://arxiv.org/abs/gr-qc/9912090 http://dx.doi.org/ 10.1088/0264-9381/17/21/303 http://adsabs.harvard.edu/abs/2000CQGra..17.4377D
Copyright:	2000, Institute of Physics
Appears in Collections:	Research Papers (TP)

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