Lie symmetries and conserved quantities of Birkhoff systems with unilateral constraints

In this paper we study the Lie symmetries of Birkhoff systems with unilateral constraints. We give the conditions for, and the form of, conserved quantities due to the Lie symmetries of the systems, and we also study the inverse problem of the Lie symmetries of the systems. Finally, an example is given to illustrate the application of the results.