Hi, I am a researcher in (analytical) philosophy. I am writing a paper on the conventionalism vs. objectvism about temporal metric, which is focused on a problem that arises before any relativistic consideration. However, in a note, I just wrote the following "the ratio between temporal lengths is frame-invariant". I tried to demonstrate it from the assumption that the space-time interval (square of dS^2 - dT^2) is frame invariant, but I got stuck :-) Could you confirm (or reject) my claim? Btw - testimony by authority would suffice Thanks a lot!