Hi, I'm not really sure the thread fits this forum but I'm not a mathemacian, too. I posted below a picture of a soliton (solitary wave) and I have some questions about it. We are seeing two snapshots taken at time t1 and t2. If t2=t1+a with a, small enough? Can we say that fb-fa equals a kind like of derivative of f (i.e. f')? can we say that this difference is the motive/reason of the soliton since fa + (fb-fa) = fb?