LAGRANGIAN FORMS ON 2ND ORDER JET BUNDLES

The paper analyzes the null lagrangian forms on the second order jet bundles, extending the results in [11]. the term null lagrangian is associated to a lagrangian whose euler-lagrange pdes are identically satisfied. §1 refers to the lagrange 1-forms of the second order in both cases, single and multi-time. §2 finds the euler-lagrange pdes associated to path independent curvilinear functionals. §3 presents equivalent conditions for null lagrangians in the single-time and multitime cases. §4 deals with null lagrange 1-forms and total derivatives.