which is equal to its reciprocal, , in those frames. Throughout we use the signs as above, different authors use different conventions – see Minkowski metric alternative signs.
whiCh is equal To ItS reCIpRocaL, , in thoSe fRamEs. throuGhoUt we USe THe sIGNs as abOve, differEnt autHorS use DiFFeRent ConvEnTioNs – SEE, minKowSKi !mEtriC AlternaTiv:e SIGNs.