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I vaguely recall reading a long time ago a 50-or-so page paper, either by John Baez or linked from his page (I think the former), which among other things gave a justification for his table of n-categories and a very cute explanation of the realization that really it should start at n=-2. I believe this paper also introduced (to me) the ideas of properties, structure, and stuff. I was just thinking about how I'd love to look back at this, but among the wealth of resources available on Baez's webpage I can't seem to find what I'm looking for. Googling hasn't turned it up either. Does anyone know what paper I'm talking about? And if it doesn't talk about properties, structure, and stuff, can anyone recommend a friendly and polished exposition of these ideas?

flag	asked Nov 8 2011 at 10:37 Aaron Mazel-Gee 3,308●6●21

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I really think much of the credit for this idea needs to go to James Dolan. But there were certainly others who were involved (e.g., Toby Bartels, David Corfield). You should read the original public discussion here: math.ucr.edu/home/baez/qg-spring2004/… – Todd Trimble Nov 8 2011 at 11:30

@Todd: Yes, I stumbled on that email thread when I was just looking around recently. It's definitely cool, but I was also hoping to find a more finished product. As well, thanks for listing the people who had a hand in this; all I could remember was that I had come across it during my read-everything-by-Baez phase. (For anyone interested, even fuller citations and an annotated bibliography are available in the paper linked below.) – Aaron Mazel-Gee Nov 8 2011 at 19:43

Gonçalo Marques · Accepted Answer · 2011-11-08 10:49:30Z UTC

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I think you mean the paper "Lectures on n-Categories and Cohomology". You can also look at the appropriate pages at the nLab.

answered Nov 8 2011 at 10:49

Gonçalo Marques
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E.g., 'negative thinking' nlab.mathforge.org/nlab/show/negative+thinking, 'stuff, structure, property' nlab.mathforge.org/nlab/show/…, and '(n,r)-category' nlab.mathforge.org/nlab/show/%28n%2Cr%29-category. – David Corfield Nov 8 2011 at 14:11

Thank you, this is exactly what I was thinking of. – Aaron Mazel-Gee Nov 8 2011 at 19:35

reference request: John Baez on (-1)- and (-2)-categories and properties+structure+stuff

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