Proper-time normalization
= Proper-time normalization
With signature $(-,+,+,+)$ and units $c=1$, parametrizing a timelike worldline by <proper time> makes its <four-velocity> satisfy $U^aU_a=-1$.
= Proper-time normalization
With signature $(-,+,+,+)$ and units $c=1$, parametrizing a timelike worldline by <proper time> makes its <four-velocity> satisfy $U^aU_a=-1$.