Refuting a Conjecture of Umans and Wang on Arithmetic-Progression Divisor Covers

Xinjie He, Amit Sahai

Any positive n-divisor arithmetic progression of height H with log H=o(√n) has length at least (√(8/27)−o(1))n^(3/4)/√log n. This excludes the proposed arithmetic-progression bounds at (α,β)=(1/3,1/3), and whenever α<1/2 and β<3/8.

Sources for this record

What was already known

Umans and Wang proposed short low-height n-divisor progressions as a stronger sufficient arithmetic-progression form of their conjectural program. The higher-rank Strong Divisor Conjecture is distinct.

AI involvement AI-led

Xinjie He and Amit Sahai say a Codex run using gpt-5.6-sol discovered the proof and initial write-up. They reviewed, verified and revised it.

The disclosure assigns discovery and initial proof to Codex, while named humans reviewed and wrote the final article; full autonomy beyond task setting is not documented.

Importance Notable

Refutes a named arithmetic-progression version of the Umans–Wang divisor conjecture with a quantitative lower bound.

Limitations

The higher-rank Strong Divisor Conjecture is a separate question and is not refuted.

Technical verification Formal (human)

The two authors explicitly report subsequent human verification of the complete proof; no machine formalization is claimed.

Formal checking

Reviewed and verified the proof and citations, then revised the exposition

Checker
Xinjie He and Amit Sahai
Scope
Theorem 1.1 AP lower bound and Corollary 1.2 exponent exclusion
Basis
Reported by the linked checker
Evidence source

Checking a formal statement does not establish that it matches the original problem.

Human understanding Full

The authors explain the fixed prime band, semiprime incidence reduction and bounded-degree linear-space estimate.

Correction and publication history

2026-10-18 · publication

Refutes a named arithmetic-progression version of the Umans–Wang divisor conjecture with a quantitative lower bound.

Read this published revision