On asymptotically flat solutions of Einstein's equations periodic in time I. Vacuum and electrovacuum solutions
arXiv:1003.3402 · doi:10.1088/0264-9381/27/5/055007
Abstract
By an argument similar to that of Gibbons and Stewart, but in a different coordinate system and less restrictive gauge, we show that any weakly-asymptotically-simple, analytic vacuum or electrovacuum solutions of the Einstein equations which are periodic in time are necessarily stationary.
25 pages, 2 figures, published in Class. Quant. Grav.