Jaén, XavierLlosa, JosepMolina, Alfred2010-05-062010-05-0619860556-2821https://hdl.handle.net/2445/12322Given a Lagrangian system depending on the position derivatives of any order, and assuming that certain conditions are satisfied, a second-order differential system is obtained such that its solutions also satisfy the Euler equations derived from the original Lagrangian. A generalization of the singular Lagrangian formalism permits a reduction of order keeping the canonical formalism in sight. Finally, the general results obtained in the first part of the paper are applied to Wheeler-Feynman electrodynamics for two charged point particles up to order 1/c4.10 p.application/pdfeng(c) The American Physical Society, 1986Teoria quànticaRelativitat especial (Física)Quantum theorySpecial relativity (Physics)info:eu-repo/semantics/article3328info:eu-repo/semantics/openAccess