Relations between symmetries and conservation laws for difference systems

Abstract

For difference variational problems on lattice, this paper presents a relation between divergence variational symmetries and conservation laws for the associated Euler-Lagrange system provided by Noether's theorem. This hence inspires us to define conservation laws related with symmetries for arbitrary difference equations with or without Lagrangian formulations. These conservation laws are constrained by some partial differential equations obtained from the symmetries generators. It is shown that the orders of these partial differential equations have been reduced comparing to the ones used in a general approach. Illustrating examples are presented.