diff --git a/src/hpc/pillar/signature.rs b/src/hpc/pillar/signature.rs index 95537c6c..c2ec3a01 100644 --- a/src/hpc/pillar/signature.rs +++ b/src/hpc/pillar/signature.rs @@ -1,4 +1,18 @@ -//! Pillar-11 — Hambly–Lyons signature transform (rough-path lifting). +//! Pillar-11 (B7) — truncated signature-kernel STABILITY battery. +//! +//! # What this certifies — and the cross-repo name collision, disambiguated +//! +//! This battery certifies **kernel stability**: PSD-ness + concentration of +//! the depth-3 truncated signature-kernel Gram over Brownian paths. It does +//! NOT certify the Hambly–Lyons uniqueness theorem — that claim lives in the +//! OTHER "Pillar 11", lance-graph's `crates/jc/src/hambly_lyons.rs` +//! (tree-quotient semantics against `sigker::signature_truncated`, +//! feature-gated). Two repos, one slot number, DISJOINT claims — a session +//! reading "Pillar 11 is green" must know which one held (found by the +//! 2026-08-31 census, `pillar11-signature-certification-unification-v1` +//! W0/F-1; the slot id B7/11 is stored history and deliberately unchanged, +//! ruling Q3: docs only). Headline reframed the same day; the transform +//! description below is unchanged. //! //! Given a path γ: [0, T] → ℝ², the **signature** S(γ) is the sequence of //! iterated Stieltjes integrals: @@ -18,10 +32,15 @@ //! and can be computed exactly in O(N · d³) time by accumulating along each //! linear segment. The kernel [`signature_d2_deg3`] implements this. //! -//! # Hambly–Lyons kernel +//! # The truncated signature kernel (historically labelled "Hambly–Lyons") //! -//! The *Hambly–Lyons sig-kernel* between two rough paths P, Q is defined as -//! the inner product of their truncated signatures: +//! The kernel between two paths P, Q is the inner product of their truncated +//! signatures — a plain truncated sig-kernel. The "Hambly–Lyons" label this +//! file attached to it is a MISNOMER kept only in the function name for API +//! stability (`sigker_hl`): HL 2010 is a *uniqueness theorem*, not a kernel +//! construction, and the label imported authority the construction does not +//! carry (census F-2, ruling Q3: docs only — the symbol stays, its doc tells +//! the truth): //! //! ```text //! k_HL(P, Q) = Σₙ₌₀³ 〈S⁽ⁿ⁾(P), S⁽ⁿ⁾(Q)〉 @@ -163,7 +182,11 @@ pub fn signature_d2_deg3(path: &[f32], n_points: usize) -> [f32; SIG_D2_DEG3_LEN // ── Hambly–Lyons sig-kernel ──────────────────────────────────────────────────── -/// Hambly–Lyons signature kernel between two paths P and Q. +/// Truncated signature kernel between two paths P and Q. +/// +/// Historically named "Hambly–Lyons kernel" here — a misnomer (HL 2010 is +/// the uniqueness theorem, not a kernel); the `_hl` symbol survives for API +/// stability, the label does not. See the module docs. /// /// Computes `k_HL(P, Q) = 〈S(P), S(Q)〉` — the Euclidean inner product of /// their degree-3 truncated signatures.