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• CommentRowNumber1.
• CommentAuthorUrs
• CommentTimeDec 22nd 2020

this is a bare list of references, to be !include-ed into relevant entries (such as D-brane, Dirac charge quantization and D-brane charge quantization in K-theory).

In fact, the list is that which has been in each of these entries all along, and it has been a pain to synchronize the parallel lists. So this here now to ease the process.

• CommentRowNumber2.
• CommentAuthorUrs
• CommentTimeJan 2nd 2021

I have made more explicit (here) the two observations that are the basis for the conjecture; and cross-linked more explicitly with Sen’s conjecture

• CommentRowNumber3.
• CommentAuthorUrs
• CommentTimeJan 2nd 2021
• (edited Jan 2nd 2021)

after mentioning of Witten’s original argument about tachyon condensation, I added this comment (here):

The closest towards an actual check of this second argument about open superstring tachyon condensation (Witten 98, Section 3) seems to be

• Theodore Erler, Analytic Solution for Tachyon Condensation in Berkovits’ Open Superstring Field Theory, JHEP 1311 (2013) 007 (arXiv:1308.4400)

which concludes with:

It would also be interesting to see if these developments can shed light on the long-speculated relation between string field theory and the K-theoretic description of D-brane charge [75, 76, 77]. We leave these questions for future work.

• CommentRowNumber4.
• CommentAuthorUrs
• CommentTimeJan 2nd 2021
• (edited Jan 2nd 2021)

which still lists (on p. 112) among open problems of string field theory:

“Are there topological invariants of the open string star algebra representing D-brane charges?”

• CommentRowNumber5.
• CommentAuthorUrs
• CommentTimeMar 15th 2021
• (edited Mar 15th 2021)

• CommentRowNumber6.
• CommentAuthorUrs
• CommentTimeApr 1st 2021

I have split off a sub-subsection “Twisted, equivariant and differential refinement”, but this still needs more work.

• CommentRowNumber7.
• CommentAuthorUrs
• CommentTimeFeb 10th 2022

For when the editing functionality is back, to add some references on the suggestion to use some kind of “holomorphic K-theory” to see D-brane charges on CYs: