Instantons and Fixed Point Actions in SU(2) Gauge Theory
  We describe the properties of instantons in lattice gauge theory when the action is a fixed point action of some renormalization group transformation. We present a theoretically consistent method for measuring topological charge using an inverse renormalization group transformation. We show that, using a fixed point action, the action of smooth configurations with non-zero topological charge is greater than or equal to its continuum value $8\pi^2/g^2$. 
Thomas DeGrand, Anna Hasenfratz, Decai Zhu