DERIVED INFORMATIVE
Mirror correspondence
Mirror maps two positions at equal distance from the conventional epoch.
A date located at +Δ from the epoch has a conjugate position at −Δ. Mirror is not a second time and does not mean that the past moves backward.
Mirror radius is |Δ| and mirror span is 2|Δ|. Conjugate LX follow from cyclic structure rather than semantic interpretation of their titles.
For integer index n, M(n) = −n. The mapping is an involution: M(M(n)) = n. Civil correspondence is R_E(t)=2E−t around epoch E.