Network, cluster coordinates and N = 2 theory II: Irregular singularity
  Cluster coordinates for a large class of Argyres-Douglas and asymptotical free theories are constructed using network on bordered Riemann surface. Such N = 2 theories are engineered using six dimensional (2, 0) theory on Riemann surface with irregular and regular singularities. The Stokes phenomenon plays an important role in our construction. Our results are expected to be very useful in studying BPS spectrum, wall crossing, and line operators of these theories, etc. In particular, we conjecture that the quiver from the network is the BPS quiver. Moreover, our construction provides a simple way to build the minimal network for cells of positive Grassmannia . 
Dan Xie
hep-th