When do the minors of a table stay positive, and what is the sharp constant in the inequality that controls them? These papers develop proofs, exact-arithmetic certificates, and the limits of the methods. Replay code checks the finite claims stated in each deposit; an all-parameter theorem also needs its proof.
Working paper + code · v2.0 · August 2026
Strict total positivity of a real Delannoy multiplication table: the sharp half-line threshold
Continue the Delannoy numbers to a real first argument and lay them out as a multiplication table. Two factorizations of the same product give two products of entries, and the more lopsided pairing always wins — exactly when x ≥ 1/2, and not one step sooner. Necessity below the threshold is explicit; sufficiency above it closes the two strips the general theory leaves open.
Working paper + code · August 2026
Odd cycles, sech spectra, and a square-tail inequality
Draw a permutation of 2r−1 letters uniformly and count its odd cycles. The Turán differences of the resulting polynomial obey a square-tail inequality, and the sharp uniform constant in it is 2.029152329129741484…, with equality only at r = 129, t = 2. The replay recomputes every certificate in exact arithmetic under separately gated chains.
Working paper · August 2026
The sharp constant in the shift-wall bridge for odd-cycle polynomials
An earlier theorem gave the bridge between two odd-cycle Turán quantities a factor of 2. Two is not the right number. The best possible constant is 2.655018313913361199726406175676…, attained exactly once, at r = 1350 and t = 2. The proof is one exceptional stripe, certified by an exact prefix and a positive-coefficient half-line certificate, and one uniform barrier.
Working paper · v1.0.1 · September 2026
What the bridge cannot see: a rank-one shadow on the positive flag
A positive sequence carries a flag of ratios, and that flag has two kernel representations differing by a rank-one term. The pinned one — a Brownian bridge on the Wallis time grid — is the better object: determinantal, with an exact gap law and a fast fixed-cardinality sampler. This paper measures what the other representation loses. The correction is a strict contraction: every flag coordinate is multiplied by a survival ratio below one, on any increasing grid.
Working paper · v1.0 · August 2026
What the ladder cannot reach: fixed-width theorems and uniform questions
Neville chamber determinants are positive at widths two, three and four, with all-row proofs. What does not follow is any bound uniform in the width, and the paper is as explicit about that as about the theorems: the fixed-width asymptotics cancel, two natural combinatorial models fail at a stated finite row, and a proposed fixed survival factor is false from order twenty on. The uniform question is left standing.
Working paper + supplement · v1.1 · September 2026
Odd cycles, mesh, and a Pick function
Count the permutations of 2n+1 objects by their odd cycles and normalize. Are the consecutive ratios positive in every forward difference at the endpoint? Yes, for every n. The row is the integer trace of one meromorphic quotient, and the zeros of its carrier are real for every n, with an exact census. With Hadamard’s theorem that census makes every logarithmic derivative along the row a sum of positive terms, one for each zero. What the spacing of the zeros adds is a representation: zeros at least one apart is equivalent to the quotient being a Pick function, proved for every n ≤ 64 and stated in general as the Watson–Herglotz conjecture. The census alone already gives the Pick property at exponent one half.
Working paper + supplement · v1.0 · September 2026
The Laguerre quotient of the odd-cycle row: moments, roots, and a limit law
Divide the odd-cycle row by a Laguerre polynomial in the finite free sense. The quotient has positive simple roots in every degree, consecutive degrees strictly interlace, and the scaled roots converge to an explicit law with a logarithmic singularity at zero and a square-root edge. The roots come from biorthogonality to one Chebyshev family, and the coefficients are moments of sums of gamma and uniform-scaled exponential variables. Moving one step along the row raises the moment order and removes two summands, and exact counterexamples show why familiar moment inequalities cannot settle that trade on their own.
Working paper · v1.0 · September 2026
The inverse hyperbolic-sinc Pick function
Invert sinh(2√A)/(2√A) = 1/(1−z) on the branch through the origin. The result maps the upper half-plane into itself, with a strictly positive density on [1, 5.6033…] in closed parametric form, and it is univalent. The proof is one conformal map, z = 1 − u/sinh u, walked once around its boundary. It is where the bulk of the odd-cycle row converges.
Working paper + code · v0.3 · August 2026
The null-diamond deficit
Put one independent fair bit at every event of an n×n causal lattice, let each future link carry one bit computed from its causal past, and ask every 3×3 bulk diamond to reconstruct its nine interior bits from the eight crossing its future cut. Counting caps each diamond’s success at 1/2. The worst-case gap to that cap is zero for n ≤ 7 and exactly 51/512 at n = 8 — an exact value, not a bound.
Software + algorithm note · v0.1.0 · August 2026
Green-path DPP
The L-ensemble matrix is dense; the computation is a path. Exact rational algorithms for finite determinantal point processes whose base matrix is built from a single decreasing sequence, with a fixed-cardinality sampler, closed one-point marginals, and replay gates that mutation controls have to fail.