FPF Reference

    C.3.A:B.2 Normative obligations for evidence design

    Preface node heading:c-3-a-b-2-normative-obligations-for-evidence-design:39603

    What this page is

    This is generated FPF reference text from the specification preface or supporting sections. It helps interpret FPF; it is not FPF Reference product documentation.

    Methodology

    Use it to understand how the specification wants to be read, then return to a route, pattern, or work packet for active work. Cite generated IDs only when the wording changes the task decision.

    Content

    EA‑1 (Two checks). Every VA/LA artifact that supports a typed claim SHALL bind both:

    • Scope predicate: U.ClaimScope(Claim) covers TargetSlice (with explicit Γ_time), and
    • Kind predicate: MemberOf(?, k, TargetSlice) is defined (deterministic).

    EA‑2 (Subkind coverage). When a claim quantifies over k, target‑contexts SHALL justify LA coverage per relevant subkind of k (or per RoleMask if masks stand in for stable subkinds). “Representative set” MUST be stated explicitly.

    EA‑3 (Independence for unions). If a published SpanUnion of evidence lines is used to enlarge covered area, independence of lines SHALL be documented (no shared weakest link).

    EA‑4 (Bridges accounted). If a VA/LA artifact travels across Contexts:

    • Scope movement SHALL use a Scope Bridge (Part B) with CL and apply the scope‑bridge penalty to R.

    • Kind movement SHALL use a KindBridge (§ C.3.3) with CL^k and apply the kind‑bridge penalty to R. Neither movement SHALL alter F or G.

      Neither movement SHALL alter F nor G.

    EA‑5 (Freshness). LA evidence SHALL declare freshness windows tied to Γ_time (no implicit “latest”). Expiry MUST fail guards closed until refreshed.

    EA‑6 (No scope‑by‑wording). Editors MUST NOT widen G by rewriting a claim to sound “more general.” Widening G (ΔG+) is permitted only with new support that truly enlarges the set of slices.

    EA‑7 (TA separation). Tool qualification (TA) SHALL be tracked independently. VA/LA guards MUST NOT substitute “tool is trusted” for content proof/coverage.

    Last Updated: 2026-06-08 — upstream FPF commit 093d30e8 (github.com/ailev/FPF)