Completed Weil positivity through support log 7
The completed centered Weil quadratic form is strictly positive for every nonzero real even test function supported in $[-R,R]$ when $R\le (\log 7)/2$. The proof identifies the form with a finite-source radial continuum operator, certifies positivity at the chamber endpoints, and transports the endpoint bounds to smaller supports by an exact dilation. A related exact matrix family is uniformly eventually positive on a shorter parameter interval.
What is proved
Write $q=4/t$ for the autocorrelation-support parameter. The complete radial continuum form $\mathfrak A_t^{\rm full}$ is strictly positive for every $t\ge 4/\log 7$, which is equivalent to completed centered Weil positivity for real even tests supported in $[-R,R]$ with $R\le (\log 7)/2$.
For the exact Jacobi-whitened matrices $W_n(tn)$, there is also a uniform eventual-positivity theorem for $t\in[4/\log 6,7.2056493]$. Every fixed ray $t\ge4/\log2$ is eventually positive as well.
The Weil-operator dictionary
The Euler-free operator $\mathfrak A_t^+$ is corrected by the finitely many prime-power translations whose logarithms lie below $q=4/t$. With $b_d=\Lambda(d)/(2\sqrt d)$ and $a_d(t)=t\log d/2$, the active terms are compressed even translations $C_{a_d(t)}$.
An exact intertwining identity identifies this radial form with one half of the completed centered Weil form. Thus the operator inequality is not an analogy or a Galerkin surrogate: it is the bounded-support Weil statement itself.
Endpoint certificates and chamber closure
At the endpoint $q=\log7$, the active atoms are $2,3,4,5$. Their exact piecewise action on shifted-Legendre modes is used to form the head matrix, the head-to-tail Gram term, and a Feshbach-Schur complement. High-precision interval congruence proves a positive tail floor and a positive finite Schur matrix.
The same architecture supplies endpoint floors for the preceding atom chambers. An exact cutoff-subspace dilation embeds every smaller support into the endpoint space, so the min-max principle transports each endpoint eigenvalue floor across its entire chamber.
- Represent each endpoint operator by exact action and moment data on the cells cut by support and reflection walls.
- Lower-bound the omitted high modes and certify the finite Schur complement by directed Arb arithmetic.
- Use the exact dilation identity and min-max to inherit positivity for every smaller support in the chamber.
Transfer to the finite matrices
Each Euler atom in $W_n(r)$ is an exact half-integer cosine compression. After adjacent parity pairing, the alias branch is suppressed on the critical frequency scale, while logarithmic-frequency compactness sends the primary branch to the corresponding continuum translation.
Mosco compactness, aggregate control of later atoms, and a parity-minus Schur floor tending like $\tfrac12\log n-O(1)$ transfer the continuum gaps uniformly through the chambers ending at $q=\log6$. The argument proves existence of a threshold $N$ but extracts no numerical value for it.
What the pinned certificate checks
The public command runs the pinned outer-chamber certificate only. It covers $t\in[4/\log2,7.2056493]$ by 424 adjacent rational interval cells and proves, on every cell, a positive tail floor, positive Schur determinant, positive congruence pivots, and nonzero preconditioner determinants.
This certificate is one of six chamber certificates used by the canonical claim. The log-3 through log-7 endpoint certificates, nesting arguments, and finite-transfer proofs are separate named source files in the claim record; the pinned outer-chamber run is a reproducible anchor, not by itself a certificate of every assertion above.
Pinned certificate
The pinned 512-bit Arb program certifies the scalar-plus outer chamber uniformly on 424 exact interval cells. It supplies one load-bearing chamber anchor; the canonical theorem also relies on separately named endpoint, nesting, and finite-transfer certificates.
uv run --frozen python canon/witnesses/C-0007/certify_interval_operator.py
canon/witnesses/C-0007/certify_interval_operator.pycanon/witnesses/C-0007/PIN.mdcanon/witnesses/C-0007/interval_operator_certificate.jsoncanon/claims/C-0007-chamber-ladder-certified-range.md
Scope
Continuum positivity is established through autocorrelation support $\log 7$; uniform eventual finite-matrix positivity is established through $\log 6$ with a non-effective threshold.
Sources
- Canonical claim
canon/claims/C-0007-chamber-ladder-certified-range.md - Pinned certificate description
canon/witnesses/C-0007/PIN.md