Algebraic structures on parallel M2 branes

In the course of closing supersymmetry on parallel M2 branes up to a gauge transformation, following the suggestion in [J. Bagger, N. Lambert, Phys. Rev. D 75 (2007) 045020, hep-th/0611108] of incorporating a gauge field which only has topological degrees of freedom, we are led to assume a certain algebraic structure for the low energy theory supposedly living on parallel M2 branes.