Secondary Trajectories in Inclusive Reactions

It is shown that some recent conjectures concerning duality in the single-particle spectrum for the reaction $a+b\to c+\mathrm{anything}$ in the fragmentation region, together with factorization, imply the cancellation of leading secondary contributions in the central region for all reactions. A simple rule without this unlikely cancellation is pointed out and discussed. Some experimental tests concerning the secondary contributions are suggested.