A further obstruction from matched symmetry

This is an obstruction to a marked covariance requirement, not merely to cone shape. It uses no continuity of the extraction rule. An unlabelled affine-isomorphism statement without the commuting condition (eq:affine-covariance) is weaker and is not covered by the proposition.

Distinguishable operational blocks, a justified revised carrier, or an explicitly restricted equivalence convention may avoid this particular premise. Numerical placements based only on identifier order do not repair matched covariance under arbitrary renaming.

Consequently, existence of a Lorentzian embedding for a poset does not imply existence of a covariant data-derived selector for it. This sharpens the set-valued-versus-single-valued distinction in XXII-C CheungXXIIC (prop:query-covariance).