On the generalized Helmholtz conditions for Lagrangian systems with dissipative forces
arXiv:1003.1840 · doi:10.1002/zamm.200900327
Abstract
In two recent papers necessary and sufficient conditions for a given system of second-order ordinary differential equations to be of Lagrangian form with additional dissipative forces were derived. We point out that these conditions are not independent and prove a stronger result accordingly.
10 pages, accepted for publ in Z. Angew. Math. Mech.