Canonical Noether symmetries and commutativity properties for gauge   systems
  For a dynamical system defined by a singular Lagrangian, canonical Noether symmetries are characterized in terms of their commutation relations with the evolution operators of Lagrangian and Hamiltonian formalisms. Separate characterizations are given in phase space, in velocity space, and through an evolution operator that links both spaces. 
Xavier Gracia (Technical University of Catalonia) and Josep M. Pons   (University of Barcelona)