Terminology for space and time, part 3

This is part 3 of an open series of posts on terminology; see part 1 and part 2.

As another way of indicating the dimensions of space and time, let space-time mean unified 3D space + 1D time, and let time-space mean unified 3D time + 1D space.

Consequently, Galilean time-space requires what I’m calling the dual Galilean transformation. And Lorentz time-space requires what I’m calling the dual Lorentz transformation.

The appropriate way of measuring the rate of movement with space-time is speed and velocity, since time is the independent variable. Pace is equivalent to the inverse of speed but their independent variables differ.

The appropriate way of measuring the rate of movement with time-space is pace and lenticity, since space (length) is the independent variable. Speed is equivalent to the inverse of pace but their independent variables differ.