A.2.6:7.4 - Why a G-ladder/levels/scales is not needed (and must not be introduced)

1) G is not an ordinal scale; it is set-valued. Under USM, U.ClaimScope is a set‑valued USM scope object over U.ContextSlice. The only well‑typed primitives are membership and set operations (⊆, ∩, ⋃). Imposing ordinal “levels” such as G0…Gk violates the type discipline and produces non‑invariant behavior (the same set could be “rated” with different numbers under different heuristics). (See also LEX‑CHR‑STRICT.)

2) G composes via ∩ / SpanUnion, not via min / avg. USM already fixes composition: along a dependent path use intersection; across independent support lines publish SpanUnion. None of these operations relies on (or preserves) any linear order. An ordinal “G ladder” invites people to take minimums/averages, which is incorrect for sets and breaks the established algebra.

3) A G ladder drags in “abstraction level,” which is orthogonal. Early “G ladders” effectively encoded abstraction/typing (instances -> patterns -> formal classes/types -> up-to-iso). That is valuable didactics, but not applicability. Abstraction is captured, if needed, by AbstractionTier (AT) as an optional facet; applicability is U.ClaimScope (G).

4) A G ladder breaks locality and Bridge semantics. When exact local senses require translation, an obtaining F.9 Bridge establishes their direct semantic relation while a separate C.2.1 claim states the proposed mapping rule and tolerated loss. There is no canonical way to translate an ordinal G level: the mapped area may be narrower or differently factored. USM translates exact sets only through that bounded claim and keeps A.10 or B.3 reliance separate rather than rewriting G.

5) A G ladder duplicates ESG guards without adding decision power. What teams often want to “compress into a G number” is actually (a) the quality of expression and (b) the completeness of the declared scope. The first is an F threshold; the second is handled by explicit guards: Scope covers TargetSlice, gammaTime is explicit only when membership varies with time, and a separate freshness-window check when current. A ladder for G adds confusion but no decision power.

Normative directive. U.ClaimScope (G) SHALL remain a set‑valued USM scope object; no ordinal or numeric ladder SHALL be defined for G. If a profile needs scalar reporting, it MAY publish an explicit report‑only proxy CoverageMetric(G), but CoverageMetric(G) MUST NOT substitute for G in norms, gates, Bridge semantics, bounded-use claims, or reliance decisions. Authoring and gating SHOULD use F thresholds (C.2.3) and explicit guard predicates (A.2.6) rather than pseudo‑levels of G.