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• CommentRowNumber1.
• CommentAuthorUrs
• CommentTimeAug 14th 2012

stub for automorphic form,to go with the blog discussion here

• CommentRowNumber2.
• CommentAuthorUrs
• CommentTimeAug 14th 2012

I have added to the Idea-section a the table that maybe nicely motivates what the whole subject is about.

• CommentRowNumber3.
• CommentAuthorzskoda
• CommentTimeAug 14th 2012

It looks like the entry should be called topological automorphic form while automorphic form should be a separate entry (I do not believe two such huge subjects can fit into a single entry).

• CommentRowNumber4.
• CommentAuthorDavid_Corfield
• CommentTimeAug 14th 2012
• (edited Aug 14th 2012)

Yes, at the moment we have modular form, topological modular form and tmf. Presumably we should have automorphic form, topological automorphic form and taf.

• CommentRowNumber5.
• CommentAuthorUrs
• CommentTimeAug 14th 2012

It looks like the entry should be called topological automorphic form

It is! :-)

• CommentRowNumber6.
• CommentAuthorzskoda
• CommentTimeAug 14th 2012

OK, created stub for classical automorphic forms and moved Norman Wallach’s reference there, and done some linking.

• CommentRowNumber7.
• CommentAuthorTodd_Trimble
• CommentTimeAug 14th 2012

It’s Nolan Wallach. I’ve made the change.

• CommentRowNumber8.
• CommentAuthorDavid_Corfield
• CommentTimeAug 14th 2012

Re the table mentioned at 2, if we have

(1,1)-dimensional Euclidean field theories and K-theory

and

(2,1)-dimensional Euclidean field theories and tmf,

are we supposed to have

(n,1)-dimensional Euclidean field theories and taf?

• CommentRowNumber9.
• CommentAuthorUrs
• CommentTimeAug 14th 2012

David,

I was asking people precisely this question today at the conference. So far nobody seems to know anything beyond that it is an evident guess. But I’ll check with further people later. Not everybody seems to have arrived yet.

• CommentRowNumber10.
• CommentAuthorDavid_Corfield
• CommentTimeAug 14th 2012

John was guessing at something like this back in TWF 197:

In particular, they show how the spectrum for complex K-theory can be built from the space of supersymmetric 1d field theories, just as the spectrum “tmf” is (conjecturally) built from some space of supersymmetric conformal field theories. Being an optimist, I can’t help but hope this pattern goes on something like this:

some cohomology theory that detects $v_n$-periodic phenomena

connections on complex “n-vector bundles”

some supersymmetric field theories on n-dimensional spacetime

• CommentRowNumber11.
• CommentAuthorUrs
• CommentTimeAug 14th 2012
• (edited Aug 14th 2012)

The last two items correlate clearly. But I am not sure how to see why it is specifically TAF that comes out for higher dimensional SQFTs. If it does.

• CommentRowNumber12.
• CommentAuthorDavid_Corfield
• CommentTimeAug 15th 2012
• (edited Aug 15th 2012)

Perhaps a crazy thought, but looking at this slide from a talk by Behrens, wouldn’t you expect an extension of the Whitehead tower to Fivebrane to give something interesting?

As you co-kill the homotopy groups, $O(n)$ comes to resemble the trivial group more closely, and we get closer to what Behrens calls $\Omega^{e}_{\ast}$, isomorphic to stable homotopy. So $\Omega^{Fivebrane}_{\ast}$ should see more $v_n$ periodic behaviour.

• CommentRowNumber13.
• CommentAuthorUrs
• CommentTimeAug 15th 2012

Perhaps a crazy thought, but looking at this slide from a talk by Behrens, wouldn’t you expect an extension of the Whitehead tower to Fivebrane to give something interesting?

Yes, certainly, that’s why the Fivebrane group is called such: just as Spin-structures make the super-particle i.e. the super 1d QFT be well-defined, and String-structures makes the heterotic string, i.e. the super 2d QFT be well defined, so Fivebrane structures similarly relate to super 6-dimensional QFT.

But, while we know that FIvebrane structures cancel the “fermionic anomaly” of the 5-brane, otherwise very little is known about that 6d QFT, as of yet.

• CommentRowNumber14.
• CommentAuthorDavid_Corfield
• CommentTimeAug 15th 2012

But what links all this to the homotopy groups of the sphere? What is the equivalent for Fivebrane of TMF for String? Is there a ring-valued genus from $\Omega^{Fivebrane}$ to some ring?

• CommentRowNumber15.
• CommentAuthorUrs
• CommentTimeAug 15th 2012

I don’t have any definite answers to these questions. It seems that most the 6-d analogs of the corresponding 2-d ingredients of the story are very much not understood yet.

• CommentRowNumber16.
• CommentAuthorUrs
• CommentTimeAug 15th 2012
• (edited Aug 15th 2012)

I have checked again with Hisham Sati. He tells me that in the 2008 talk where he talked about Fivebrane structures, he already stated a conjecture that there will be a morphism from $\Omega^{Fivebrane}$ to topological automorphic forms. I didn’t know about that, to be frank.

If I find out more that I may share, I’ll let you know.

• CommentRowNumber17.
• CommentAuthorzskoda
• CommentTimeAug 15th 2012

Thanks Todd for Nolan. It sliped my mind. Is anybody having a fie of his book on Fourier transform and symplectic geometry. It is a simple old book whose simplicity made me always easily remember the stuff. But I have not seen it since leaving United States…

• CommentRowNumber18.
• CommentAuthorDavid_Corfield
• CommentTimeAug 15th 2012

Re 16, that would seem to be a good move to link your work up to topological automorphic forms. There does seem to be considerable interest.

If I have this height business correct, I think Fivebrane would pick up $v_6$ periods. It seems that K3-cohomology can get up to height 10, and the Shimura variety approach could get to any height.

• CommentRowNumber19.
• CommentAuthorhilbertthm90
• CommentTimeAug 16th 2012

Wow. I wrote up the page height of a variety over a year ago. I’m shocked that it comes up in this topic. My thesis work has a lot to do with height, p-divisible groups, and liftability for K3 surfaces and Calabi-Yau threefolds and the relation to the derived category. This is very interesting since the motivation was very different for me.

• CommentRowNumber20.
• CommentAuthorDavid_Corfield
• CommentTimeAug 17th 2012

Anything on the link between height and detection of $v_n$ periodic behaviour would be good to add, e.g., Ravenel on p. 15 of these slides.