Since a big deal is made about the fact that Jamil's hobby is the study of the representation theory of Lie groups, I was both surprised and disappointed that he and his hero did not discuss any mathematics. But then, that's not the focus of the story. It is about life...and death.

It is noted that Jamil lives in the (virtual) city of Noether, named after Emmy Noether, and that the planet is Laplace. As for the toroidal structure of their universe, it is stated that "The topology of this universe lets you see the back of your head, but never your reflection."

By the way, the idea of "quantum soccer", is that team members on a playing field must manipulate the harmonics of a quantum wave function in order to get most of the wave (a certain amount of its probability, if you want to think in terms of the Copenhagen interpretation of QM) into the opponents net. Egan even let's you play the game through a Java applet on his website!

Publication history

• Interzone #148, October 1999.
• The Year's Best Science Fiction: Seventeenth Annual Collection, edited by Gardner Dozois; St. Martin's Press, New York, 2000.
• Year's Best SF 5, edited by David G. Hartwell; HarperPrism/Avon Eos, New York, 2000.
• Hayakawa's SF Magazine, March 2001. (Japanese translation)
• Supermen: Tales of the Posthuman Future, edited by Gardner Dozois; St. Martin's Press, New York, 2002.
• “Guardie di confine” in Cinquant'anni di Futuro, Mondadori/Urania, Milan, 2002. Translated by Roberto Marini. ISSN 1120-5288 / Number 1450 (The Urania SF line is published as a paperback periodical.) (Italian translation)
• Reasons to be Cheerful and Other Stories (collection, Hayakawa) Translated by Makoto Yamagishi. (Japanese translation)
• The Locus Awards, edited by Charles N. Brown and Jonathan Strahan; Harper/Eos, New York, 2004.
• Available Online for Free at Egan's website.