More On Gauge Theory And Geometric Langlands

Understand

The geometric Langlands correspondence was described some years ago in terms of $S$-duality of $\N=4$ super Yang-Mills theory.

• Some additional matters relevant to this story are described here.
• The main goal is to explain directly why an $A$-brane of a certain simple kind can be an eigenbrane for the action of 't Hooft operators.
• To set the stage, we review some facts about Higgs bundles and the Hitchin fibration.