15#15 means that there are four independent supersymmetry transformations. This is the maximum possible supersymmetry for a gauge theory in four dimensions.

The gauge theory is believed to be well defined non-perturbatively through e.g. a lattice regularization.

Many people have worked in this area. For the older work I give here only a few representative references and apologize to all those not cited.

Jorge Pullin
Mon Sep 7 17:37:02 EDT 1998