This monograph has grown out of research we started in 1987, although the foun dations were laid in the 1970's when both of us were working on our doctoral thes

It is well known that symmetry-based methods are very powerful tools for investigating nonlinear partial differential equations (PDEs), notably for their reduct

This volume contains the contributions of the participants of the 13th International ISAAC Congress 2021, held in Ghent, Belgium. The papers, written by respect