 This principle, when combined with the light postulate (and certain other assumptions), leads to the Lorentz transformations, these being the transformations between coordinate systems moving uniformly with respect to one another according to STR. According to STR the laws of physics are invariant under Lorentz transformations, and indeed under the full Poincaré group of transformations. These transformations differ from the Galilean transformations of Newtonian mechanics. H. Minkowski reformulated STR, showing that space and time are part of a single four-dimensional geometry, Minkowski spacetime. In this way, the Poincaré group of symmetry transformations is part of the structure of spacetime in STR, and for this reason these symmetries have been labelled “geometric symmetries” by Wigner (1967, especially pp. 15 and 17–19).