TOPOLOGICAL DENSITY AND INSTANTONS ON A LATTICE

We present an update on the study of topological structure of QCD. Iss ues addressed include a comparison between the plaquette and the geome tric methods of calculating the topological density. We show that the improved gauge action based on root 3 blocking transformation suppress es the formation of topologically charged dislocations with low action . Using a cooling method we identify the instantons' location, estimat e their size and density, and calculate the renormalization constant Z (Q) for the plaquette method.