 In a richer theory one would also like to describe the interactions of baryons with pions.A fully relativistic Lagrangian of nucleons is non-predictive as the quantum corrections, or loop diagrams can count as formula_1 quantities and therefore do not describe higher-order corrections.Because the baryons are much heavier than the pions, HBChPT rests on the use of a nonrelativistic description of baryons compared to that of the pions.