Exts and the AGT Relations

We prove the connection between the Nekrasov partition function of N= 2 super-symmetric U(2) gauge theory with adjoint matter and conformal blocks for the Virasoro algebra, as predicted by the Alday–Gaiotto–Tachikawa relations. Mathematically, this is achieved by relating the Carlsson–Okounkov Ext v...

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Bibliographic Details
Main Author: Negut, Andrei
Other Authors: Massachusetts Institute of Technology. Department of Mathematics
Format: Article
Published: Springer-Verlag 2018
Online Access:http://hdl.handle.net/1721.1/115960
https://orcid.org/0000-0002-1622-8638
Description
Summary:We prove the connection between the Nekrasov partition function of N= 2 super-symmetric U(2) gauge theory with adjoint matter and conformal blocks for the Virasoro algebra, as predicted by the Alday–Gaiotto–Tachikawa relations. Mathematically, this is achieved by relating the Carlsson–Okounkov Ext vector bundle on the moduli space of rank 2 sheaves with Liouville vertex operators. Our approach is geometric in nature, and uses a new method for intersection-theoretic computations of the Ext operator. Keywords: Nekrasov partition function, AGT relations, Ext operators, shuffle algebra