Nonlocal symmetries and formulae for generation of solutions for a class of diffusion–convection equations

New formulae of nonlocal nonlinear superposition and generation of solutions are proposed for nonlinear diffusion–convection equations which are linearizable or are invariant with respect to a generalized hodograph transformation or connected by this transformation. We study in what particular ways additional Lie symmetries of diffusion–convection equations induce nonlocal symmetries of equations obtained from the initial ones by nonlocal transformations. The formulae derived are used for the construction of exact solutions.