Conservation law 2 Continuous symmetry 2 Difference equations Differential-difference equations 2 Failure (mechanical) 2 Independent variables 2 Mapping 2 Noether's theorem 2 Noether's theorems 2 Preserving mappings 2 Simple++ 2 Structure-preserving 2 Symmetry 2 Transformation 2 conservation laws 2 differential-difference equations 2 symmetries 2 transformations 2