V.D19 — Geodesic Duration

The geodesic duration between causally ordered events alpha_m < alpha_n is Delta t(m,n) := t(n) - t(m) = sum_{k=m}^{n-1} p_k^{-1}, the arc-length difference on tau^1. It is monotonically decreasing in tick size (later ticks shorter) and the total duration t_infinity is finite.