created a brief entry *IKKT matrix model* to record some references. Cross-linked with *string field theory*, and with *BFSS matrix model*

I have expanded the Idea-section at *AGT correspondence*, saying more explicitly how this may be thought of as regarding the 6d (2,0)-theory as a “2d SCFT with values in 4d SYM theories” and added pointers to further references (including some reviews).

I have similarly expanded/added brief remarks on AGT/generalized S-duality pointing to this at *6d (2,0)-SCFT – Compactification on Riemann surface* and at *S-duality – for SYM – From compactification*

I have split off from *holographic principle* and then expanded a good bit a few paragraphs on

*AdS3-CFT2 and CS-WZW correspondence*

together with a few commented references, trying to amplify how this case is given by an actual well-known theorem and at the same time seems to be generic for the more general cases of AdS-CFT which are currently much more vague.

]]>added a bunch of pointers to the literature (with brief comments) at *string scattering amplitude*.

Also added a corresponding paragraph at *effective field theory*.

(this is still in reaction to that MO discussion, specifically to the question here)

]]>created *black holes in string theory*, since somebody asked me: a brief paragraph explaining how the entropy-counting works and some references.

I am trying to give more of the entries of the brane scan in low ambient dimension their proper names.

Next to the little string in $D = 6$ the brane scan says that there is a Green-Schwarz action functional for a 3-brane $\sigma$-model in $D = 6$. This has been first written down in

- James Hughes, Jun Liu, Joseph Polchinski,
*Supermembranes*, Physics Letters B Volume 180, Issue 4, 20 November 1986, Pages 370–374

but it seems to go by no specific name apart from “the 3-brane in 6d”. So I created a stub entry with that title, *3-brane in 6d*.

added a bunch of references to *M2-brane*

I have started adding references to *string field theory* , in particular those by Jim Stasheff et al. on the role of L-infinity algebra and A-infinity algebra. Maybe I find time later to add more details.

I have added to string theory a new section Critical strings and quantum anomalies.

Really I was beginning to work on a new entry twisted spin^c structure (not done yet) and then I found that a summary discussion along the above lines had been missing.

]]>am in the process of adding some notes on how the D=5 super Yang-Mills theory on the worldvolume of the D4-brane is the double dimensional reduction of the 6d (2,0)-superconformal QFT in the M5-brane.

started a stubby *double dimensional reduction* in this context and added some first further pointers and references to *M5-brane*, to *D=5 super Yang-Mills theory* and maybe elsewhere.

But this still needs more details to be satisfactory, clearly.

]]>started *topologically twisted D=4 super Yang-Mills theory*, in order to finally write a reply to that MO question we were talking about. But am being interrupted now…

created *worldline formalism* to go with this Physics.SE answer

added to the people-entry *Edward Witten* a paragraph *Fields medal work* with a commented list of articles that according to Atiyah won Witten the Fields medal in 1990.

I gave the brane scan table a genuine $n$Lab incarnation and included it at *Green-Schwarz action functional* and at *brane*.

started a bare minimum at *Poisson-Lie T-duality*, for the moment just so as to have a place to record the two original references

Since it touches on several of the threads that we happen to have here, hopefully I may be excused for making this somewhat selfish post here.

For various reasons I need to finally upload my notes on “differential cohomology in a cohesive ∞-topos” to the arXiv. Soon. Maybe by next week or so.

It’s not fully finalized, clearly, I could spend ages further polishing this – but then it will probably never be fully finalized, as so many other things.

Anyway, in case anyone here might enjoy eyeballing pieces of it (again), I am keeping the latest version here

]]>started some minimum at *exceptional field theory* (the formulation of 11d supergravity that makes the exceptional U-duality symmetry manifest)

started *M-theory on G2-manifolds*

created stub for 6d (2,0)-supersymmetric QFT, mainly to record the references for the moment

]]>added a handful of further references to *Witten genus*, with brief comments.

Also ended up splitting off a stub for *sigma-orientation*.

I suppose with all the entries on Witten genus and related what was missing was an entry titled *Dirac-Ramond operator*. So I created one and filled in a bare minimum.

*Sen’s conjecture* (and a stub for *D25-brane*)

(to go with this physics.SE discussion)

]]>I started splitting off *elliptic genus* from *Witten genus* but got interrupted. So currently it’s essentially just a stub.

I am adding to the $n$Lab further pointers here and there on Witten’s story $6d SCFT \stackrel{KK}{\to} 4d SYM \stackrel{KK}{\to} Langlands$. Added now to *self-dual string* a pointer to (Witten 95), which I suppose is the first observation of the self-dual string and its ADE classification.

I have tried to clarify a bit more at *Kaluza-Klein monopole*, and at *D6-brane*