Mass Gap Again
I am curious about something. As Distler pointed out in June, in a post discussing Witten's new $Z(q)$, which is polynomial in the $J$ invariant, Witten emphasized in his talk [on 2+1D gravity] that the gauge theory approach is wrong. Does this mean that the Mass Gap problem needs to be rephrased? After all, the official statement begins with the words: prove that for any compact simple gauge group G, a non-trivial quantum Yang-Mills theory exists. Why would we care about this nonsensical question if it's the wrong question? Surely the Mass Gap of interest is the physical one.
By the way, the Hoehn paper mentioned in Distler's post looks like an interesting application of lattices and codes.