Abstract
Magnetic translation operators that generate symmetries of a Bloch electron in a constant uniform magnetic field are shown to span the sine bracket algebra which is the unique Lie algebra deformation of the area-preserving diffeomorphisms of a two-torus. The deformation parameter is identified with the number of magnetic flux quanta through a unit cell of the substrate lattice. The symmetries of a spin-1/2 Bloch electron are shown to realize the supersymmetric extension of the sine bracket algebra.