Approximate Symmetry in Nonlinear Physics Problems One-Dimensional Flows of a Polytropic Gas:Lie Group Classification, Conservation Laws, Invariant and Conservative Difference Schemes Hamiltonian Structure and Conservation Laws of Three-Dimensional Linear Elasticity Theory Complex Methods for Lie Symmetry Analysis Symmetry Analysis and Conservation Laws of a Family of Boussinesq Equations Group Analysis of the Guant and Pu Model of Option Pricing and Hedging On Involutive Systems of Partial Differential Equations Group Analysis of Some Camassa-Hohn-Type Equations Partial Invariance and Problems with Free Boundaries Group Properties of the Riemaun Function
