Noncommutativity In A Simple Toy Model
  We discuss various symmetry properties of the reparametrization invariant toy model of a free non-relativistic particle and show that its commutativity and noncommutativity (NC) properties are the artifact of the underlying symmetry transformations. For the case of the symmetry transformations corresponding to the noncommutative geometry, the mass parameter of the toy model turns out to be noncommutative in nature. By exploiting the Becchi-Rouet-Stora-Tyutin (BRST) symmetry transformations, we demonstrate the existence of the NC and show its cohomological equivalence with its commutative counterpart. A connection between the usual gauge symmetry transformations corresponding to the commutative geometry and the quantum groups, defined on the phase space, is also established for the present model at the level of Poisson bracket structure. We show that, for the NC geometry, such a kind of quantum group connection does not exist. 
R. P. Malik (Bose National Centre & CAS, Phys. Deptt., BHU)