On the symmetry and conservation law classification of the de Sitter–Schwarzschild metric and the corresponding wave and Klein–Gordon equations

The main purpose of this work is to focus on a discussion of Lie symmetries admitted by de Sitter–Schwarzschild spacetime metric, and the corresponding wave or Klein–Gordon equations constructed in the de Sitter–Schwarzschild geometry. The obtained symmetries are classified and the variational (Noether) conservation laws associated with these symmetries via the natural Lagrangians are obtained. In the case of the metric, we obtain additional variational ones when compared with the Killing vectors leading to additional conservation laws and for the wave and Klein–Gordon equations, the variational symmetries involve less tedious calculations as far as invariance studies are concerned.

Symmetries, pseudosymmetries and conservation laws in Lagrangian and Hamiltonian k-symplectic formalisms

In this paper, we will present Lagrangian and Hamiltonian [Formula: see text]-symplectic formalisms, we will recall the notions of symmetry and conservation law and we will define the notion of pseudosymmetry as a natural extension of symmetry. Using symmetries and pseudosymmetries, without the help of a Noether type theorem, we will obtain new kinds of conservation laws for [Formula: see text]-symplectic Hamiltonian systems and [Formula: see text]-symplectic Lagrangian systems.

SYMMETRY AND CONSERVATION LAW CLASSIFICATION AND EXACT SOLUTIONS TO THE GENERALIZED KdV TYPES OF EQUATIONS

In this paper, complete geometric symmetry and conservation law classification of the generalized KdV types of equations are investigated. All of the geometric vector fields and second-order multipliers for the equations are obtained, and the corresponding conservation laws of the equations are presented explicitly. These comprise all of the second-order conservation laws for the equations. Furthermore, an analytic method is developed for dealing with the exact solutions to the generalized nonlinear partial differential equations with composite function terms.