Abstract:
The classification of differential autosubstitutions of the form $\hat u=G(u_x,u)$ that are allowed by general evolution equations with one spatial variable is considered. In the one-field case, every such substitution can be reduced to the autosubstitution $\hat u=u+u_x/u$ for the Burgers equation by a point transformation. This substitution is generalized to the two-field case.
Citation:
V. S. Novikov, “Equations invariant under differential substitutions”, TMF, 116:2 (1998), 193–200; Theoret. and Math. Phys., 116:2 (1998), 890–895