WHY IM 1 NF RELATION BETWEEN THE CROSS-SECTIONS FOR GAMMA-GAMMA-]PI(0)PI(0) AND PI(+)PI(-)-]PI(0)PI(0) CANNOT BE RIGHT/

Using a 1/N(f) expansion of a general chiral lagrangian, Im has claime d to derive a powerful relationship between the partial waves for gamm agamma --> pi0pi0 and those of pi+pi- --> pi0pi0, namely that their ra tio is a universal function of energy. We prove that the differing thr eshold behaviour of these amplitudes does not allow such a relation to be true. We illustrate this with an explicit example. Im's result fai ls because of an implicit assumption that off-shell four pion amplitud es have no off-shell dependence : an assumption that is only true for point interactions, which physical pions do not have.