In this paper, group analysis of the time fractional Harry-Dym equation with Riemann–Liouville derivative is performed. Its maximal symmetry group in Lie’s sense and the corresponding optimal system of subgroups are determined. Similarity reductions of the equation under study are performed....

We perform Galilei symmetry group classification of a class of third-order nonlinear evolution equations in one spatial variable, which generalize KdV and mKdV equations. All inequivalent PDEs belonging to the class in question which admit the classical Galilei group, the extended Galilei group...