Lie point symmetry for an ODE

Is a particular case of the generalized symmetry of an ODE. In this case

Y = ξ (x, u) \partial x + η (x, u) \partial u + \sum_{i = 1}^{m - 1} η^{i} (x, u^{(m - 1)}) \partial u_{i}

where $ξ, η \in C^{\infty} (R^{2})$ , and $η^{i}$ satisfies the same prolongation formula than generalized symmetries:

η^{i} (x, u^{(m - 1)}) = A (η^{i - 1}) - A (ξ) \cdot u_{i} .

Lie point symmetry of a DE system

Is the 1-dimensional case of a symmetry group of a DE system.