\section{Acknowledgements}
\label{ack}

The work was performed with Lockheed Independent Research funds under 
project RDD506.  We are also grateful to the people 
with Wavetracer, in particular Mary Cacciatone, Mike Lee, Tom McLaughlin 
and Robert Shuffleton.  They made their machine available 
to us and gave freely of their time in advice and in assisting 
our debugging efforts.  We would like to thank the people at MasPar,
Don Rector in particular, for the use of their machine. 
Thanks to Mark Noga at Lockheed PARL for his technical assistance.
We also thank the referees of DIMACS 
for their comments, and for bringing the Auction method to our attention.