On the symmetries of evolution equations

Abstract

GONTENTS § 0. Introduction § 1. Finite dimensionality of the algebra of classical symmetries § 2. Finite-dimensional subalgebras of K3 § 3. Subalgebras of K3 and differential substitutions § 4. Group substitutions for systems of evolution equations § 5. Differential substitutions of the first order § 6. Pseudo-symmetries § 7. Soliton symmetries References