Playing With the Index of M-Theory

Commun Math Phys. 2022;396(2):817-865. doi: 10.1007/s00220-022-04479-7. Epub 2022 Aug 23.

Abstract

Motivated by M-theory, we study rank n K-theoretic Donaldson-Thomas theory on a toric threefold X. In the presence of compact four-cycles, we discuss how to include the contribution of D4-branes wrapping them. Combining this with a simple assumption on the (in)dependence on Coulomb moduli in the 7d theory, we show that the partition function factorizes and, when X is Calabi-Yau and it admits an ADE ruling, it reproduces the 5d master formula for the geometrically engineered theory on A n - 1 ALE space, thus extending the usual geometric engineering dictionary to n > 1 . We finally speculate about implications for instanton counting on Taub-NUT.