# LIB2-245 — Retired physical use of the PSL class-algebra sign argument

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

## Statement

The earlier class-algebra argument used a vanishing structure constant to select the sign of a leptonic phase formula; the current print types δCP = −2π/√5 = −160.997° Derived-conditional (Rev29 re-tiering; the pre-Rev29 stamp was Theorem ⋆100), from the V3 rotation and not from that argument.

## Caution

The pure class-algebra constants survive, and the old phase expression remains only as a labelled cross-check.

## Primary source

Paper 8, §2, Retired physical use of the class-algebra constants, PDF p.122: "That application is deprecated. The authoritative CP phase is δCP = −2π/ 5 = −160.997◦ from the V3 rotation (Derived-conditional after the Rev29 re-tiering; pre-Rev29 stamp ⋆100; Paper 5, Appendix C), which does not involve PSL(2, 7) at all;"

## Machine

- url: /library-v2/LIB2-245/
- content_sha256: 00120f5b500ac07f8e790412999e5274f674825a14429d467cfa8c03b2a9816b
- candidate_ids: C2-172

## Freshness

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