FPF Reference

A.2.6:17. 4 Rationale - F‑Cluster Unification for A.2.6 (F.17 / F.18)

Preface node heading:a-2-6-17-4-rationale-f-cluster-unification-for-a-2-6-f-17-f-18:4573

Content

Intent. This annex applies the F‑cluster method to triangulate USM terms against a diverse set of post‑2015 sources and communities (“Contexts”), and then fixes the Unified Tech and Plain names used in A.2.6. Results are ready for downstream lexicon entries (Part E) and guard templates (ESG / Method–Work).

F.17 Unified Term Survey (UTS) — Method & Scope

Contexts surveyed (SoTA, diverse):

  1. ISO/IEC/IEEE 42010 (architecture description)
  2. OMG Essence (Kernel: Alphas, Work Products, States)
  3. NIST AI RMF 1.0/1.1 (trustworthy AI)
  4. ASME V&V 40–2018 / FDA 2021–2023 (model credibility)
  5. W3C SHACL (2017+) / SHACL‑AF (data constraints)
  6. OWL 2 / ontology engineering (2012+, current practice)
  7. IETF BCP 14 (RFC 2119/8174) (normative keywords & guard style)
  8. DO‑178C + DO‑333 (avionics, formal methods supplement)
  9. ISO 26262:2018/2025 (automotive functional safety)
  10. IEC 61508 (2010+, current revisions) (basic safety)
  11. ACM Artifact Review & Badging v1.1 (reproducibility signals)
  12. MLOps/Cloud SLO practice (SRE / platform) (operational guardrails)

Survey focus (terms we align): U.ContextSlice, generic Scope and set algebra, Claim scope (G), Work scope, Bridge & CL, Γ_time, widen/narrow/refit/translate, SpanUnion / serial intersection, separation from F and R, avoidance of overloaded validity/operation terms.

UTS Table (F.17) — Cross‑context term mapping

#Context / SourceLocal label(s) (native)Closest USM conceptNotes on fit & deltas
1ISO/IEC/IEEE 42010Architecture context; environment; stakeholder concerns; viewpoints/viewsContextSlice (addressable slice); Scope as view‑specific applicability42010 is about views in context; it has no first‑class set‑valued scope char but aligns with “evaluate in a concrete context” → USM uses explicit slice tuples.
2OMG EssenceAlpha State; Work Product State; Level of Detail (LoD)Work scope (guards), Detail (D) (LoD), ESG/RSGEssence separates status (states) and work evidence; LoD is detail, not scope. USM treats scope as guardable membership over slices; states/LoD map to ESG & D, not to G.
3NIST AI RMFContext of use; validity, reliability, robustness; monitoringClaim scope (G); R freshness/monitoring“Context of use” = where a claim/model holds → maps to G. “Validity” is part of R vocabulary; we avoid naming the characteristic “validity” to prevent LA confusion.
4ASME V&V 40 / FDAContext of use; credibility factors; verification/validationClaim scope (G); R (credibility)Direct fit for G via “context of use”. Credibility/evidence freshness contribute to R, not to G; USM keeps them separate in guards.
5W3C SHACLShapes; targets (sh:targetClass, sh:target); constraintsClaim scope (targets define where constraints apply); F≥4 (predicate form)SHACL “target” ≈ membership predicate on a dataset context; perfect analogue of Claim scope on data slices; constraint language supports F4‑style predicates.
6OWL 2 practiceClass extension; domain/range; imports/version IRIClaim scope as class extension over an ontology contextClass extension is set‑semantics by design; G naturally maps to extension over a versioned ontology (part of ContextSlice).
7IETF BCP 14MUST/SHALL/SHOULD; requirements languageGuard style (observable predicates)BCP 14 doesn’t define scope but dictates how guards are worded; USM aligns by requiring observable, deterministic membership checks.
8DO‑178C / DO‑333Operational conditions; DAL; formal method objectives; TQLWork scope (operating conditions); F (proof‑grade), R (assurance objectives)Operational applicability = Work scope; formal method objectives lift F; Tool qualification impacts TA/R, not G.
9ISO 26262Operational situation & operating modes; ASIL; OSEDWork scope (operating modes/situations)OSED/operating modes define where capability can be exercised → Work scope. Assurance level (ASIL) relates to R, not G.
10IEC 61508SIL; demand mode; proof test intervalWork scope (demand vs continuous mode) + R freshnessMode concepts influence where/how a function can be claimed → Work scope; proof test interval sits in R (freshness/decay).
11ACM ArtifactsAvailable/Evaluated/Reusable; Reproduced/ReplicatedR signals; ContextSlice (reproduction environment)Badges encode evidence availability/strength; the declared environment maps to a slice; scope of claim is often implicit → USM makes it explicit.
12SRE / Cloud SLOSLOs; error budgets; regions/tiers; rollout windowsWork scope (regions/tiers/windows) + measures; Γ_time policiesSLOs attach measures within a Work scope (region/tier/time window); perfect fit for USM Method–Work guards (WG‑1..3).

Summary. Across all Contexts, two stable notions recur: (1) evaluate in a concrete context (→ U.ContextSlice), and (2) declare where something holds/is deliverable (→ set‑valued Scope). “Context of use,” “operating modes,” “targets,” “class extension,” and “OSED” are all Context‑flavored presentations of Claim scope or Work scope. Terms like validity and operation are semantically close but collide with LA and FPF’s Work/Run lexicon; we therefore do not adopt them as characteristic names.

F.18 Term Selection — Unified Tech & Plain names

Selected names (normative)

Concept in A.2.6Unified Tech (lexicon)Unified Plain (manager‑friendly)Allowed short formDeprecated / avoid
Addressable evaluation contextU.ContextSliceContext sliceSlice (when local)“domain” (as guard input), “latest” time
Abstract mechanism (set‑valued)U.ScopeScope—“applicability”, “envelope”, “validity” (as characteristic names)
Episteme applicabilityU.ClaimScope (*nick G)Claim scopeG“generality”, “applicability/envelope (of claim)”
Capability applicabilityU.WorkScopeWork scope“capability envelope”, “operational applicability”, “operation scope”
Time selectorΓ_timeTime selector—implicit “latest”
Cross‑context mappingBridge + CLBridge + congruence levelCLsilent reuse across Contexts
Parallel coverageSpanUnionUnion of supported areas—unqualified “union” without independence
Serial dependencyIntersectionIntersection of scopes—ordinal “more/less general” language
Scope editsΔG+ (widen), ΔG− (narrow), Refit, TranslateWiden, narrow, refit, translate—stealth widening (“it’s obvious”)
Optional didacticsU.Detail (D), U.AbstractionTier (AT)Detail / abstraction tierD / ATusing AT/D as G substitutes

Why these names (decision grounds):

  • “Scope” wins over “envelope/applicability/validity”. It is short, self‑documenting, and already idiomatic in SRE/SW, while “validity” clashes with Validation Assurance (LA) and “envelope” suggests geometry, not membership.
  • “Claim scope” vs “Work scope”. Two‑word compounds meet the FPF clarity rule: the first token reveals the carrier (Claim vs Work/Capability), the second the mechanism (scope).
  • Keep G. The F–G–R triple is canonical; we retain G as nickname for Claim scope.
  • “Context slice” is the only term that makes the evaluation target addressable (Context, versions, params, Γ_time).
  • “Operation/operating/validity” avoided. They are overloaded in existing FPF lanes (Work/Run, LA) and create policy ambiguities in guards.

Phrasebook (for editors, normative)

  • Use “Claim scope (G) covers TargetSlice” and “Work scope covers JobSlice” in guards.
  • Always spell Γ_time; never say “latest”.
  • To compose, say: “intersection along dependency paths; SpanUnion across independent support lines.”
  • For Cross‑context use, say: “via Bridge; CL penalties apply to R (trust), not to F/G (content/scope).”
  • When widening/narrowing, write “ΔG+ / ΔG−” and log the support change; use “Refit” for unit/param normalization.

Rosetta summary (informative, for rationale box)

local context phraseUse in USM wording
“Context of use” (NIST, ASME/FDA)Claim scope (G) on explicit Context slice
“Operating modes/situations” (ISO 26262)Work scope with measures & qualification windows
“Target (class/shape)” (SHACL/OWL)Claim scope predicates (membership)
“Architecture view context” (42010)Context slice + Scope checks inside the view
“Capability envelope” (legacy safety docs)Work scope
“Domain” (informal)Context slice elements; not acceptable as a guard input

Outcome. The UTS shows strong convergence across SoTA Contexts on addressable context and set‑valued applicability. F.18 therefore fixes: Context slice, Scope, Claim scope (G), Work scope, Publication scope with the algebra and guard clauses mandated in A.2.6. This closes synonym drift while remaining readable for engineering managers and precise for assurance tooling.