I am trying to understand notion of a "Dehn twist" and how it relates to topological order.
In particular refering to http://arxiv.org/abs/1208.4834 it is stated that Xiao Gang Wen's paper on "Topological Order in Rigid States" (http://dao.mit.edu/~wen/pub/topo.pdf) is supposed to provide an introduction to "non-abelian adiabatic Berry phases associated with Dehn twists for a U(1) Chern Simons Theory". Skimming through the respective paper however I could not find the notion of a "Dehn twist" appearing at all? Maybe it appears under a different name or it is not given a name at all?
I would be very happy for any support.