Hirota-Satsuma dynamics as a non-relativistic limit of KdV equations
Résumé
• There exist well-defined non-relativistic and ultra-relativistic limits of coupled KdV equations. • These limits are related to the underlying symmetry structures. • The ultra-relativistic limit is relevant to high-energy physics, but pathological. • The non-relativistic limit is well defined provided there is an order-one coupling between left-movers and right-movers.