Now let us return to the various types of worlds we have discussed in the preceding paragraphs. It is possible to give an alternative presentation of the results mentioned. Thus, we start from the mathematical expression of
:
where
represents the invariant velocity without any specification as to its value. (It may be infinite, as in classical science, or equal to Maxwell’s constant
, as in Einstein’s theory, or even equal to some imaginary number, as in the case last discussed.) Then it can be shown that by dividing this equation by
