Skip to main content
13 events
when toggle format what by license comment
Apr 13, 2017 at 12:57 history edited CommunityBot
replaced http://mathoverflow.net/ with https://mathoverflow.net/
Mar 10, 2010 at 1:04 comment added Chris Schommer-Pries I added the tqft tag since I think it is of interest to people interested to tqfts.
Mar 10, 2010 at 1:03 history edited Chris Schommer-Pries
added tag: tqft
Mar 9, 2010 at 21:05 history edited Bruce Westbury CC BY-SA 2.5
Link added
Mar 9, 2010 at 9:38 vote accept Bruce Westbury
Feb 24, 2010 at 10:14 comment added Bruce Westbury Here is a reference where this is done. MR2169040 Gliske, S. ; Klink, W. H. ; Ton-That, T. Algorithms for computing generalized ${\rm U}(N)$ Racah coefficients. Acta Appl. Math. 88 (2005), no. 2, 229--249.
Feb 23, 2010 at 21:21 comment added Greg Kuperberg Allen: Yes, you can define a numerical 6j-symbol given any system of canonical bases of $\text{Inv}(A \otimes B \otimes C)$, where "canonical" is taken in the informal sense. More formally, you can (a) use Lusztig's dual canonical bases; or (b) simply ask for any self-consistent set of formulas. A consistent set of formulas would define the bases with respect to which they are correct.
Feb 22, 2010 at 9:06 comment added Bruce Westbury Allen, The decomposition of an exterior power with any representation is unique. The question was phrased to avoid this problem. I defined the 6j-symbols as the components of a functor. In general this would mean specifying bases in vector spaces and there is no consensus on how to do this (but there are several ways it can be done). You put a vector at each vertex of the tetrahedron graph to define a scalar.
Feb 20, 2010 at 15:05 comment added Allen Knutson In SL(2) the decomposition of 2-fold tensor products is unique, prompting one to compare the decomposition of $(A \otimes B) \otimes C$ with $A \otimes (B\otimes C)$. But for other groups the decomposition isn't unique, without some canonical basis input perhaps. So it's never been clear to me how to define 6j symbols, much less compute them.
Feb 19, 2010 at 17:24 answer added Pavel Etingof timeline score: 14
Feb 19, 2010 at 15:22 comment added Bruce Westbury I agree. Kirillov and Reshetikhin stated the result. Masbaum and Vogel proved it by showing both sides satisfied the same linear recurrence relations. Frenkel and Khovanov derive the result. The Frenkel and Khovanov method is the only one which looks as though it could be applied in other examples.
Feb 19, 2010 at 14:43 comment added Greg Kuperberg I think that the result for sl(2) is due to Kirillov and Reshetikhin, and that these other references are later, although they may give new arguments.
Feb 19, 2010 at 8:31 history asked Bruce Westbury CC BY-SA 2.5