NOTE ADDED IN PROOFRecently, Flaschka, Forest, and MacLaughlin (report at the Soviet-American [Conference on Solitons, Kiev (1979), September] showed that the system of equations for the functions Ej(x, t) in the case of the Korteweg-de Vries equation can be written in a beautiful invariant form 0 12 0 dP.~ =0, 0~-d~176 -where the differentials d~] 0 and d~ i have the form (4.11), and, in particular, in the form*) which is simpler than (4.13), (4.16), (4.21), (4.22). However, the question of the existence of solutions Ej(x, t), j = 0 ..... 21 corresponding to the problem of the collision of wave trains remains open even for the equations written in the form (*). In the expansion of the solutions Ej(x, t) in the parameter T -i characterizing the magnitude of the nonlinearity of the original equation (4.2}, (*) provides no practical simplifications. TAUBERIAN THEOREMS IN QUANTUM FIELD THEORY