No time machines in classical general relativity
Abstract
Irrespective of local conditions imposed on the metric, any extendible spacetime U has a maximal extension containing no closed causal curves outside the chronological past of U. We prove this fact and interpret it as impossibility (in classical general relativity) of the time machines insofar as the latter are defined to be causalityviolating regions created by human beings (as opposed to those appearing spontaneously).
 Publication:

Classical and Quantum Gravity
 Pub Date:
 August 2002
 DOI:
 10.1088/02649381/19/15/316
 arXiv:
 arXiv:grqc/0111054
 Bibcode:
 2002CQGra..19.4109K
 Keywords:

 General Relativity and Quantum Cosmology;
 Mathematics  Differential Geometry
 EPrint:
 A corrigendum (to be published in CQG) has been added to correct an important mistake in the definition of locality