is the total cross-section of electron-positron annihilation into muon pairs, in the We conclude that both F1(w) and F2(w) change sign at w = 1 if the nucleon w~1 that F2(w) : C((w— 1)2"+1, n : 0, 1, (nucleon current), (42) F2(w) : Cn(w~ I)“, .