Definition: Event-time and history-label calibration

For distinct $t_k$:

1. exact event-time calibration at a fixed reading event $e$ means

   $$p_k>0⟹t_k=T(e);$$

2. history-label calibration means that a supplied event map $\kappa$ satisfies $T(\kappa (k))=t_k$. A reading at $e_r$ labels $\kappa (k)$, not necessarily $e_r$.