Acknowledgements

I'd like to thank the following people for their suggestions and patches (in no particular order): Roberto Alsina, Waldo Bastian, Harri Porten, Samuel Wuethrich, Richard Moore, Daniel Naber, Ralf Nolden, Martin Konold, and Pietro Iglio, Stephan Kulow, Junji Takagi.

I'd also like to thank everyone who wrote to me with words of encouragment and thanks.