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Positivity and counterexamples for rising-factorial Toeplitz determinants

Henry Zweiman · September 22, 2026 · P57 · Version 1.0

A separate manuscript addressing Karp's 2012 Conjectures 1, 2, 4, 5, and 6. The earlier Conjecture 3 paper remains separate.

Conjecture Result
1 Proved for all positive shift parameters.
2 and 5 Disproved by an exact stability counterexample with a positive strictly log-concave input.
4 The literal assertion fails for degenerate inputs; a general minor expansion gives coefficient nonnegativity and exact criteria for degree and strict positivity.
6 Disproved for determinant order three using the degree-eleven binomial sequence.

The counterexamples have integer-arithmetic certificates, not merely numerical root estimates. The manuscript develops the general positive expansions explicitly and credits the standard tools used. Historical priority has not been established.

Prepared with OpenAI Codex; not peer reviewed or independently verified by a human expert.

Reproduce

Run python3 checks/verify.py with SymPy installed. Run python3 build.py with Pandoc and Tectonic on PATH, or specify their executable paths through PANDOC and TECTONIC. The build writes manuscript.tex and manuscript.pdf beside the source.