Penrose on Spin Networks

Here's a classic paper on spin networks that was previously available only in an out-of-print book:

Roger Penrose, Angular momentum: an approach to combinatorial space-time, in Quantum Theory and Beyond, ed. T. Bastin, Cambridge University Press, Cambridge, 1971, pp. 151–180. Available in PDF and Postscript, or as LaTeX source code.

This electronic version was prepared by Georg Beyerle. Roger Penrose has given me his permission to make it available here.

Here's another, also prepared by Georg Beyerle:

Roger Penrose, On the nature of quantum geometry, in Magic Without Magic, ed. J. Klauder, Freeman, San Francisco, 1972, pp. 333–354. Available in PDF and Postscript, or as LaTeX source code.

Here are some notes, apparently passed from Roger Penrose to Lee Smolin, then to Scott Morrison, and then to me:

Roger Penrose, Theory of quantized directions, handwritten notes, 1971. Available in PDF.

Related papers include: