Symmetries, Lagrangian Formalism and Integration of Second Order Ordinary Difference Equations

Symmetries and linearization of ordinary difference equations

The connection between symmetries and linearizations of discrete-time dynamical systems is being inverstigated. It is shown, that existence of semigroup structures related to the vector field and having linear representations enables reduction of linearization problem to a system of first order partial differential equations. By means of inverse of the Poincaré map one can relate symmetries in ...

On Lie Group Classification of Second{order Ordinary Difference Equations

Classification of Second-order Ordinary Differential Equations Admitting Lie Groups of Fibre-preserving Point Symmetries

We use Elie Cartan's method of equivalence to give a complete classification, in terms of differential invariants, of second-order ordinary differential equations admitting Lie groups of fibre-preserving point symmetries. We then apply our results to the determination of all second-order equations which are equivalent, under fibre-preserving transformations, to the free particle equation. In ad...

Lecture 18: Ordinary Differential Equations: Second Order

2. General Remarks Second order ODEs are much harder to solve than first order ODEs. First of all, a second order linear ODE has two linearly independent solutions and a general solution is a linear combination of these two solutions. In addition, many popular second order ODEs have singular points. Except for a few cases, the solutions have no simple mathematical expression. However, there is ...

On certain types of point symmetries of systems of second-order ordinary differential equations

Existence criteria for some generic types of point symmetries of systems of n-second order ordinary differential equations are studied, specially in connection with the generation of semisimple subalgebras of symmetries belonging to the simple linear and orthogonal types, as well as their maximal dimension and rank. The structure of certain time-dependent symmetries, in particular scaling symme...