Greg Egan is an Australian science fiction author, with several articles in the journal Classical and Quantum Gravity to his name. His writing is very ‘hard’, in the sense that it contains lots of scientific and mathematical detail. Egan contributes images to John Baez‘s blog Visual Insight.
There are famously no pictures of him on the web.
Along with J. Daniel Christensen, Greg Egan presented an algorithm, written in C++, to understand the asymptotic behavior of the 10j symbol, a spin network that arises in the partition function for the Barrett-Crane model? of 4d Riemannian quantum gravity. This partition function is the summation over all spin labelings of the faces in the dual 2-skeleton of a fixed triangulation of spacetime, applied to an expression which contains the product of a 10j symbol for each dual vertex.
J. Daniel Christensen and Greg Egan, An Efficient Algorithm for the Riemannian 10j Symbols arxiv:gr-qc/0110045v3
John C. Baez, J. Daniel Christensen, and Greg Egan. Asymptotics of 10j Symbols Classical and Quantum Gravity 19, no. 24 (December 21, 2002): 6489–6513. arXiv:gr-qc/0208010
About the special orthogonal groups SO(3) and SO(4):
Explanation, visualisation and calculation of the first homology of the Hantzsche-Wendt manifold:
Applets:
Euler characteristic applet (1997)
Gravitational Waves applet (1997)
Decoherence applet (2002)
Spin Networks applet (2002)
Last revised on November 12, 2025 at 05:11:02. See the history of this page for a list of all contributions to it.