

5 Acknowledgments
Most of this work was prepared while I was funded by a grant from
DFG. I also benefitted from the MPI for Mathematics in the
Sciences, Leipzig, where the article was completed. I wish to thank
H. Friedrich for explaining some of the more subtle issues of
null-infinity, and in particular of
, to me. Thanks are
also due to P. Hübner for providing me with some of the
figures in Section 4.4. I also want to thank
Ted Newman and Roger Penrose for filling me in on some of the
historical developments of the subject. Finally, I want thank
M. Hein and T. Vogel for carefully reading through the
manuscript and checking the equations.
This work was prepared partly during the workshop
“Gravitational interaction of compact objects” at the KITP in Santa
Barbara. It was supported in part by the National Science
Foundation under Grant No. PHY99-07949.

