According to Gukov et al. in this 2017 paper Seiberg-Witten theory in 4d *categorifies* Seiberg-Witten theory in 3d. In what sense is this phrase mentioned? I know what the process of categorification is (e.g. how Khovanov homology categorifies Jones polynomial).

**What is the exact relation between the 3d and 4d versions of Seiberg-Witten theory and in what sense is the latter the categorification of the former?**

"Monopoles and 3-manifolds"by Kronheimer-Mrowka. $\endgroup$1more comment