Abstract:
Some theorems are proved concerning the structure of Lagrangian systems
of differential equations for which the Lagrangian is not uniquely determined. In particular, a complete description is obtained for bi-Lagrangian systems of second order with hyperregular Lagrangians quadratic in the derivatives.
Citation:
F. A. Lunev, “Field-theory models that admit alternative Lagrangian formulations. I”, TMF, 89:1 (1991), 121–131; Theoret. and Math. Phys., 89:1 (1991), 1098–1105