Multitime Rayleigh Solitons
  Multitime evolution PDEs for Rayleigh waves are considered, using geometrical ingredients capable to build an ultra-parabolic-hyperbolic differential operator. Their soliton solutions are found based on appropriate hypotheses and specific ODEs. These multitime solitons develop complex behavior of deformation phenomena. The original results include: the form of multitime Rayleigh PDEs, the construction of multitime Rayleigh solitons via some significant amounts of analysis and the stability of multitime Rayleigh solitons, which are stable enough to persist indefinitely. In this context we survey some of the highlights of multitime PDEs theory, from the more classical single-time case, to the more recent multitime case, as well as current developments in using this theory to rigorously prove the sense for several evolution variables and PDEs. 
Laura Gabriela Matei, Constantin Udriste
math-ph math.MP