Lagrangian descriptions of dissipative systems: a review
In this paper, we review classical and recent results on the Lagrangian description of dissipative systems. After hav-
ing recalled Rayleigh extension of Lagrangian formalism to equations of motion with dissipative forces, we describe
Helmholtz conditions, which represent necessary and sufficient conditions for the existence of a Lagrangian function for
a system of differential equations. These conditions are presented in different formalisms, some of them published in the