# LIB2-040 — An RB-even action cannot select the horizontal-orbit sign

- class: CLAIM · review_state: PUBLISHED · house_tier: not yet assigned
- labels as printed: math_status NOT_PRINTED · attachment NOT_PRINTED · scorecard tier word none (PDF p.167)
- basis: {"pdf_sha256_prefix": "b64ddcd9e16a6dcd", "release": "Rev33.1_S369"}

## Statement

For X in the registered horizontal 16-dimensional sector, every RB-conjugation-invariant scalar obeys S(exp(2tX)) = S(exp(−2tX)), so an RB-even action cannot resolve that sign.

## Caution

This symmetry obstruction requires an RB-odd ingredient somewhere; it does not itself construct or select that ingredient.

## Primary source

Appendix E, §6(v), Even-action sign obstruction, PDF p.173: "An RB -even action cannot resolve the sign — the parity of the law, not its strength, is what fails."

## Machine

- url: /library-v2/LIB2-040/
- content_sha256: f1b7528434a495572f8ab5326545f4ebecf65eb5891c196bb308676232cbe6c6
- candidate_ids: C2-105

## Freshness

- BUILD_STAMP S371a · 2026-09-26T22:53Z · master 01d1a5873ede42f5 · cut 9dcc6ce9a8ee3e02
- Declared volatile fields (R36): BUILD_STAMP