Figure 1. Feynman diagrams showing the most important (tree-level) contributions to the axial and pseudoscalar three-point functions. The squares correspond to explicitly inserted operators: the right and left ones correspond to smeared three-quark baryon interpolating currents at the source (at time 0) and the sink (at time t ), respectively, while the ones in the middle depict a pseudoscalar or an axialvector operator insertion (at time (cid:28) ). The circles correspond to pion-nucleon interaction vertices, while the dashed and solid lines represent pion and nucleon propagators, respectively. The dotted red vertical lines indicate the sums over hadronic states one usually introduces to interpret correlation