added pointer to:

- Danhua Song, Mengyao Wu, Ke Wu, Jie Yang,
*Higher Chern-Simons based on (2-)crossed modules*, JHEP**2023**207 (2023) [arXiv:2212.04667, doi:10.1007/JHEP07(2023)207]

I started working on making this cluster of entries all exist and have content:

But I got bogged down a bit with working on all the cross links. Now my battery is dying…

]]>I have added discussion of why the abelian Chern-Simons action is nontrivial precisely in dimensions $(4k+3)$ for $k \in \mathbb{N}$.

Then I vaguely indicated the holographically related self-dual theories for the first few values of $k$

$(k = 0)$: 3d CS / 2d string

$(k=1)$: 7d CS / 6d fivebrane

$(k=2)$: 11d CS / space-filling 9-brane of type II

added the definition to higher dimensional Chern-Simons theory. Not done yet, but have to interrupt now.

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