Section 1 analyses some elements of the geometry produced on jet bundle of order one by a semi-Riemann Sasaki-like metric.Section 2 describes the maximal integral manifolds of a distribution as solutions of a PDEs system of order one.Section 3 studies the Poisson second- order prolongations of first order PDE systems and formulates the Lorentz-Udriste World-Force Law on a suitable semi-Riemann-Lagrange manifold (the base manifold of the jet bundle of order one).Section 4 exploits the idea of least squares Lagrangians, to include the integral manifolds of a distribution into a class of extremals. Section 5 refers to the canonical forms of the vertical metric tensor produced by a density of energy on jet bundle of order one.
Mathematics Subject Classification:53C43, 31C12, 58E20, 37J99