 The form of the Galilean transformations shows that, in addition to being affine transformations, they also preserve metrical relations on time and space. Distinct inertial frames will agree on simultaneity, and on (ratios of) time-intervals; they will also agree on the spatial distance between points at a given moment of time. Therefore, in the four-dimensional picture, the decomposition of space-time into hypersurfaces of absolute simultaneity is independent of the choice of inertial frame. Another way of putting this is that Newtonian space-time is endowed with a projection of space onto time, i.e. a function that identifies space-time points that have the same time-coordinate. Similarly, absolute space arises from a projection of space-time onto space, i.e. a function that identifies space-time points that have the same spatial coordinates. See Figure 6. 